Frequently Asked Questions

Don’t frustrate yourself trying to interpret the pH of pure water.  In principle, very pure water should indeed have a pH of 7.0, but usually it is 5 to 6 because atmospheric CO2 dissolves readily into the water to produce carbonic acid.  Some deionizers will produce perfectly pure water that is nevertheless slightly alkaline, pH 7.5 – 8.  Check your pH calibration instead with cream of tartar.

NOTE: in most cases, calibration problems can be addressed by steps 1-6 below. If your electrode is slow or showing numbers way out of range, try the meter test FIRST (steps 13-16 below). The reconditioning steps (7 – 12) should not normally be needed on an electrode that is less than 6 months old.

1. Be sure your electrode has been stored at least 24 hours in a proper electrode storage solution (Vinmetrica’s product is 3M potassium chloride in 10 mM potassium hydrogen phthalate; other similar products may be used). The entire bottom 1 inch of the electrode needs to have been submerged for at least 24 hours. If this has NOT happened, wait until it has!
2. IMPORTANT! Always stir or gently agitate the solution when using the pH electrode; letting it sit static will cause drift and inaccurate readings!
3. When calibrating your pH electrode, remember that the displayed pH may not be correct until AFTER you press ENTER, and the “Good Cal” message finishes scrolling.
4. If the instrument signals stable pH (i.e., the Cal LED is flashing) but displays “Bad Cal” after pressing ENTER, try putting it flat on the table; when the next stable pH is signaled, press the ENTER button quickly without handling the instrument. Sometimes the instrument may pick up noise from its environment, particularly if you handle it at the last second, while it’s trying to achieve a stable reading.
5. If values appear to drift, leave the electrode in the pH 4.01 reference solution for 30 minutes.
6. If you intend to read pH values in samples that are at a different temperature than ambient, it’s best to have your reference solutions at that temperature also before calibrating.
7. You can restore the pH calibration and bias (DAC setting) values to factory defaults in Test Mode (see Appendix A, Section 13 in your manual). Contact tech support if you have questions beyond this.

Reconditioning and cleaning of pH electrodes

Note: before you try the procedures that follow in steps 8-12, try the simple step of soaking the electrode in your pH 4.01 reference solution for about 1 hour, then try to calibrate. Sometimes this is all that’s needed!
Even in normal use and storage, performance of pH electrodes may show deterioration over time, which typically shows up as noisy, erratic or sluggish electrode readings, and/or difficulty calibrating. Assuming the meter itself is working (see “Meter test” below), then there are two main causes for this:
A. Clogging of the reference junction (most likely).
B. Fouling of the glass membrane (happens occasionally, or after prolonged service).
The following procedures will often provide renewed stability and pH sensitivity. If the electrode cannot be restored by one of these methods, it needs to be replaced.

Unblocking the reference junction:
The reference electrode junction is usually the problem when the electrode can’t calibrate in its expected ranges. This junction is a fine-pored frit that allows electrical contact of a reference electrode with the solution being tested. It can become clogged over time.
8. Soak electrode in hot (NOT boiling!) water, about 60 °C, for 5 – 10 mins. Allow to cool to room temperature then place in pH 4 reference solution for 5 minutes. Try to recalibrate. If this does not work, try the next step.
9. Place electrode in electrode storage solution (from Vinmetrica, or 3M KCl with optionally added 0.01M potassium acid phthalate, KHP) at 60 °C and allow electrode and solution to cool to room temperature, then place in pH 4 reference solution for 5 minutes. Try to recalibrate. If this does not work, try the next step.
10. Soak in 0.1M HCl (note: this can be made by diluting 1 mL of the SO2 Acid Solution with 20 mL DI water) or HNO3 for 1 hour. Rinse with DI water, then place in pH 4 reference solution for 5 minutes. Try to recalibrate. If this does not work, try the next step.
11. Soak in 1:10 dilution of bleach in a 0.1 – 0.05 % solution of liquid detergent in hot water with vigorous stirring for 15 mins. Rinse with DI water, then place in pH 4 reference solution for 5 minutes. Try to recalibrate.

Cleaning the pH electrode’s glass membrane:
The glass bulb is a thin membrane of a special kind of glass that actually does the job of responding to the pH of the solution. It can sometimes become dirty and poorly responsive.
12. Immerse electrode tip in 0.1M HCl (see above for how to make) for about 15 secs., rinse with distilled water, then immerse in 0.1M NaOH (you can use a little of your TA Titrant for this) for another 15 sec. Cycle the electrode through these solutions several times (rinsing with DI water in between), then rinse and check for performance in pH buffer 4.00 and 7.00.

Meter test

You want to be sure that the instrument is responding correctly. A quick test is to simply short out the electrode connector:
13. Put the instrument in pH mode.
14. Remove the electrode to expose the BNC connector at the back of the instrument. Short out the terminals on the connector, using a paper clip or similar metal piece to touch the center pin of the connector to its outer metal sheath.
15. With the input shorted out, the reading should be pH 7.00 +/- 0.5. If out of this range, the meter is probably bad. Contact us.
16. Bear in mind that this test is not 100% fool-proof (the instrument might still have trouble reading pH values different from 7.00), but generally if this test passes, it is much more likely to be an electrode problem.

pH test with cream of tartar

A quick way to check your calibration and pH accuracy is to measure the pH of a saturated solution of cream of tartar which has a pH of 3.56 at 25 degrees celsius:
a. Get pure cream of tartar (grocery store stuff is fine, provided it’s pure), or even better is reagent grade potassium hydrogen tartrate, also known as potassium acid tartrate or potassium bitartrate. Call it KHT for short.
b. Place about 1/4 teaspoon of KHT in 20 mL of distilled water. Mix well for about 30 seconds. You want to be sure the solution is saturated, i.e., everything that can dissolve, has dissolved. There should be some undissolved solid left.
c. Decant or filter the solution off the solids.
d. This solution has a standard pH of 3.56 at 25 degrees C (78 degrees F). It should be within 0.02 pH of this value at temperatures from 20 to 30 degrees Celsius. Discard after 24 hours.

After calibrating the unit in both the 4.01 and 7.0 solutions in my house, I go out to test my 52 degree wine tank. Is that okay?

The SC-300 does not have temperature compensation (ATC), however the difference in a pH measurement between 52F and 70F for most solutions is pretty small, less than 0.05 pH units in most cases depending on what the solution is.

If you need to make measurements at 52F, for best accuracy we recommend calibrating with 4 and 7 solutions that are at that temperature. You can do this by storing your pH calibration solutions in the same room as your wine tanks.

You can check calibration at room temperature with a saturated solution of cream of tartar (potassium hydrogen tartrate, KHT for short). Add 1/8 tsp KHT to 20 mL distilled water, stir for 30 sec. pH is 3.55 at 70F. At lower temperatures the saturated KHT is not standardized, but will be between 3.50 and 3.60, so you can confidently check your calibration at 4 and 7 this way.

The ability to test pH with ATC may be an available feature in 2021. Keep an eye our for any announcements in our newsletters.

Additional Information:
There is very little variance of the pH measurement of wine if you are operating within plus or minus 27 degrees F (+/- 15°C) of room temperature, 77° F. The table below will let you know what are typical readings from the pH meter using our reference solutions or other buffers at different temperatures. If you operate the pH meter close to room temperature, 77° F (approximately 25°C) , with the wine sample and the reference solutions also close to room temperature, you should have acceptably accurate measurements with a variance +/- 0.02 pH units.

If you are operating in outdoor conditions or in a cold cellar, the chart below should let you know how much variance is to be expected regarding pH buffers and our pH 4 and 7 reference solutions as well. Since most wines fall within a pH range 3.0 to 4.0, you can roughly approximate the variance in pH to be similar to a pH 3 buffer, a pH 3.49 check solution (50 mM sodium diglycolate), and the pH 4.01 reference solution provided with the SC-200 and SC-300. Even a change in temperature of +/- 27°F from room temperature doesn’t change the pH more than +/- 0.03 pH units with the three solutions mentioned above, so unless you are operating below 50°F or above 104°F, the pH measurements accuracy due to temperature variation is very close to the error of the instrument (+/- 0.02 pH).

The reason that the pH of wine drops on adding distilled water has nothing to do with the water or, up to a point, with the degree of dilution. Rather it has to do with the nature of the pH electrode and how it measures pH. pH is generally considered to be -log[H+], i.e., the negative logarithm, base 10, of the hydrogen ion concentration, but formally it is defined as -log(hydrogen ion activity). Activity a and concentration c are related but not identical: a = g x c where g is the “activity coefficient”. It is this coefficient that is changing as you dilute your wine, becoming closer to 1 with dilution. The pH electrode responds to hydrogen ion activity, rather than its concentration per se.

Also, since wine is a fairly strongly buffered system (primarily by the tartaric acid/tartrate ions, and other acids present) you would have to dilute it over a thousand fold to change the hydrogen ion concentration.

To check your pH calibration, suspend about 1/8 tsp (0.5 g) of pure cream of tartar (aka potassium hydrogen tartrate) in 20 mL of water, stir to dissolve for 30 sec. Some crystals will remain. This saturated solution of cream of tartar has a standard pH at 25C of 3.56. I am good with 3.50 to 3.60. If not, try recalibrating. Make this fresh each day.

A better way to test the validity of pH calibration is to measure the pH of a saturated solution of cream of tartar.

1. Get pure cream of tartar (grocery store stuff is fine, provided it’s pure), or reagent grade potassium hydrogen tartrate, also known as potassium acid tartrate or potassium bitartrate. Call it KHT for short.
2. Place about 1/8 teaspoon of KHT in 20 mL of distilled water. Mix well for about 30 seconds. You want to be sure the solution is saturated, i.e., everything that can dissolve, has dissolved. There should be some undissolved solid left.
3. Decant or filter the solution off the solids if possible.
4. This solution has a standard pH of 3.56 at 25 degrees C (78 degrees F). It should be within 0.02 pH of this value at temperatures from 20 to 30 degrees Celsius. We usually are OK with a value between 3.50 and 3.60. Discard after 24 hours

It is possible to measure the pH of distilled water, but it’s tricky. In principle pure water has a pH of 7.00 at normal temperatures, but as atmospheric CO2 dissolves in the water the pH will drop slightly due to the formation of carbonic acid. In addition, most distilled water from the store, (which by the way is usually de-ionized, rather than distilled), may have very minor amounts of acidity or alkalinity that takes the pH away from 7.00. So even if you degas and boil the water, you may find the pH still not hitting 7.00 and in any case it will start changing immediately on exposure to air.

However, the pH of your distilled water is unimportant for almost anything you want to do with it, because the water has negligible buffering ability. If you were to take 25 mL of it and do a TA titration for example, you will see that less than 1 drop of TA Titrant takes it to way above pH 9, so in essence it has no detectable acidity.

The 0.133N NaOH (TA Titrant) that we make is specifically designed to be used with our kit when testing your TA levels. You can use the 0.1N NaOH as a replacement for the TA Titrant however there will need to be adjustments made to your final calculations. You cannot use the simple equation listed at the end of the procedure (TA = 2 * V). You will need to use the longer equation listed above it and replace the 0.133N with the concentration of the NaOH solution that you use. This may blur your endpoint slightly so do take care when performing the titration and make sure to not overshoot the endpoint.

Place the electrode back in the storage solution as soon as possible. It may come back to life. Soak the probe in the storage solution (but make sure this solution is clean and clear) for a few days and then try and calibrate it and see what happens. If you do not have fresh storage solution you can soak it in the pH 4.01 reference solution until you are able to get fresh pH electrode storage solution.

The best way to add acidity is: slowly and carefully! As discussed in this BLOG post, add half the amount you think you need, then re-check pH and TA to see where you are.

When you add acidity with tartaric acid (as we recommend) then the TA just goes up by the amount you added (in g/L).  As we’ve discussed in the above mentioned blog post, the decrease in pH that this effects depends on the TA (buffering) ability of the wine.

Yes, you can use the SC-300 (or -200) to determine total acidity in vinegar. Assuming it is a typical acid strength of 5%, that would be 50 mL/L as acetic acid, which is the same as 50 g/liter (density of acetic acid liquid is 1.0). So, 50 g/L divided by 60 g/mol acetic acid means it would be about 0.83 mol/L acetic acid.  In 1.0 mL then, there would be 0.83 mmol of acetic acid. This would take 0.83/0.133 or about 6.2 mL of the TA Titrant (which is 0.133 mmol/mL) to titrate completely.

Here’s the procedure:

1. Measure out as precisely as possible 1.00 mL of your vinegar into a small beaker or other titration vessel.
2. Add about 20 mL of distilled or deionized water.
3. Attach and Insert the pH electrode (it’s a good idea to calibrate it ahead of time). Begin gentle stirring or swirling
4. Put your SC-300 in TA mode and titrate with TA Titrant per the usual method to pH 8.2; record the mL of TA Titrant used as ‘V’.
5. Calculate:

% acetic acid by volume =  0.798 * V

or, if you use some other NaOH Titrant and/or a different volume of sample:
% acetic acid by volume = 100% * V * N * 60 / (S * 1000)

where N is the NaOH Titrant strength (0.133 in our case), and S is the sample volume in mL (1.00 in our case).

The pH 4 reference solution (for use with the SC-200 or SC-300 unit + pH electrode) is now labeled as 4.00, the correct reference value at a temperature of 20 ℃ (68 ℉).  The chemical composition of the solution itself is unchanged from before, and its reference value is still 4.01 at 25 ℃ (77 ℉). It’s just that since most of us work on wine or other beverages that are closer to 15 to 20 ℃ (59 to 68 ℉), a value of 4.00 is slightly more accurate than 4.01. Instruments that use the old reference value 4.01 rather than the new value of 4.00 do not produce significant error: less than 0.02 pH difference in wines with pH values from 3.00 to 4.00.

As mentioned in a recent newsletter, we have a new update to the firmware for SC-200s and -300s built after 2015 (Serial numbers 2897 and above for SC-300s, 470 and above for SC-200s).  This new firmware, versions 3.2.F (or 2.2.F for an SC-200) and higher, uses the value of 4.00 instead of 4.01 for pH calibration.  All new units being shipped will now have this new firmware version installed on them. If your instrument has a lower serial number, or an earlier version of firmware, it will set the pH 4 reference to 4.01 as usual.

This is a common occurrence with several explanations, any or all of which may be happening:

1. Make sure you are using fresh sulfite powder. Potassium metabisulfite degrades over time and that stuff you bought 2 years ago is probably bad now!
2. Make sure that you stir your wine thoroughly when you add sulfite. If you pour a 10% solution of KMBS into your wine, it sinks like a battleship! A sample taken off the top will read low unless the wine is stirred.
3. A significant portion of the sulfite you added may have ended up ‘bound’, particularly if your free SO₂ was very low to begin with. This bound SO₂ does not show up when you measure free SO₂, and it is not protecting your wine. You will need to add more sulfite until your free SO₂ comes up to the right level. Sometimes you must add 2 or even 3 times more sulfite than you first calculated.

Vinmetrica’s SC-100 (and SC-300) gives results that are right in line with aeration oxidation (AO) and segmented flow analysis:

Vinmetrica’s instruments correlate very well with other methods

Also check out Dan Pambianchi’s article “Benchmarking of SO2 Analysis Instruments and Methods” on the Home Winemaking Resources page of the Techniques in Home Winemaking website:

http://www.techniquesinhomewinemaking.com/attachments/File/Benchmarking of SO2 Analysis Instruments and Methods.pdf

Refer to this troubleshooting guide for help: https://vinmetrica.com/troubleshooting-guide/#SO2Problems

For SO₂ measurements with the SC-300 or the SC-100A, there are several quick tests you can do to make sure the instrument is not faulty.

First, if your instrument does not have the latest firmware version 1.1.2, 3.1.2, or 3.2.d, we recommend that you always start with the electrode disconnected. After powering on the instrument (and, on the SC-300, pressing ENTER to confirm SO₂ mode), then connect the SO₂ electrode. This avoids incorrect background settings that may make the instrument appear to be insensitive or unresponsive. To determine which firmware version you have, go into Test Mode (see Appendix A in your manual, or HERE)

To test the functioning of the instrument:

1. Be sure the battery is good per the manual’s instructions.

2. Remove the electrode to expose the BNC connector at the back of the instrument. Turn on the instrument and select SO₂ mode. Short out the terminals on the connector, using a paper clip or similar metal piece to touch the center pin of the connector to its outer metal sheath. The device should indicate “STOP” with its red LED and buzzer or beeper. If this does not happen there may be a problem with the instrument; contact us for more information.

3. Connect the electrode and put it in about 20 mL of distilled water; add about 1 ml (half a bulb squeeze) of each of the acid solution and the reactant and swirl in the usual way keeping constant motion. The instrument may or may not indicate STOP as above. If it does not, add a drop of the SO₂ Titrant solution. This should make the STOP condition occur. [If it doesn’t you may have an electrode problem read in the next section below how to fix this.] Now add one drop of a concentrated sulfite solution (1-10% is fine) and verify that the STOP signal ends and the PROCEED light illuminates. If this happens, your electrode is probably OK as well.

4. Finally, you can check your SO₂ reagents with the SO2 Standard Test.

Preconditioning of the electrode Note: as of October 2013, all SO2 electrodes are shipped pre-conditioned, so this procedure should not normally be needed. Sometimes when the SO₂ electrode is first shipped it can be shipped “hot”. A hot electrode is one that is overly sensitive as indicated by high readings (and STOP conditions) when inserted into solutions that should be giving no signal, like pure water or water plus reactant and acid with a drop of 10% KMBS added. If your electrode shows this behavior, it generally can be fixed by pre-conditioning as follows:

1. First, turn the power on and press the MODE button until the instrument is in SO₂ mode, then press ENTER. Attach the SO₂ electrode to the SC-300 analyzer. Put 20 mL of distilled water (deionized water) in a beaker and add half a bulb squeeze of the acid solution, half a bulb squeeze of the reactant solution and let the SO₂ electrode sit in this solution.

2. Then add one drop of 10% potassium metabisulfite solution (KMBS) to the beaker with the electrode in it. Swirl gently. The instrument LCD should now read 0.0 (in units of nanoamps) or close to it. If it is reading significantly higher than 20 on the screen, let the electrode sit in the solution for half an hour.

3. After half an hour rinse the electrode with distilled water. Put it in about 20 mL of distilled water. Again add half a bulb squeeze of each of the acid solution and the reactant and swirl in the usual way keeping constant motion. The instrument may or may not indicate STOP as above. If it does not, add a drop of the SO₂ Titrant solution. This should make the STOP condition occur. [If it doesn’t you may have an electrode problem]

4. Now add one drop of KMBS solution (1-10% is fine), swirl and verify that the STOP signal ends and the PROCEED light illuminates. If this is the case, your electrode has been conditioned. If the electrode is still “hot” and the PROCEED light does not illuminate, let it sit in 20 mL of distilled water with a half bulb full of the acid solution for a few hours. Now repeat the test from step 3. If it works, great! If not, call us and we will try to troubleshoot or replace your electrode. Our contact information is at the bottom of the page.

We don’t recommend it because if you cross-contaminate any of the solutions you can cause yourself a major headache in trying to untangle crazy results. But yes, you can do this to save your Titrants but always make sure you are putting it back in the correct bottle.

This is most likely an issue with contamination. If they are severely contaminated, the Acid and Reactant will need to be replaced.

It is normal if the Reactant solution has a slight yellow tinge but that typically happens over the course of a few years. The Acid should stay clear. The Acid solution can turn yellow if trace iron gets into it (which is not a problem usually) , or possibly if the Reactant solution comes in contact with it (which can be a problem). Also, the chemical composition of the Reactant is such that it can sometimes develop that yellow color. [If you want to send us a photo so that we can verify this, we would be more than happy to take a look at it. You can send it to info@vinmetrica.com.]

A quick test you can run will tell you if the Acid and/or Reactant is compromised enough to warrant replacement.  Check here: https://vinmetrica.com/troubleshooting-guide/#LiquidSO2Test

Also, the two squeeze bulb pipettes that are provided in the kit should be marked for either the Acid or the Reactant and used only on their specified solution.

We have created this handy Electrode_Guide to guide you in selecting the correct SO2 electrode. Remember, you are selecting the SO2 electrode termination so find the picture of the instrument that matches your instrument and select the electrode that matches up to it.

Our SO2 Reactant and SO2 Titrant are proprietary solutions. The SO2 Acid Solution is 2 molar (2M, or about 6% by weight) hydrochloric acid (HCl).

You can find the SDS sheets for all our reagents at https://vinmetrica.com/safety-data-sheets-sds/

When testing for Free SO2, if you follow the procedures in the normal way and you end up using 5mL + 2.6mL more from a second syringe then your calculation at the end would not need to change. You would simply multiply total volume by 20 as stated in the manual, which would be 7.6*20 = 152

If you know you have high SO2 values and you want to use less of your SO2 Titrant (to conserve your reagents) you can use 10mL of your wine, add 15mL of DI water and then follow the remaining steps as usual, adding your Reactant and Acid solutions and titrating with the SO2 Titrant. This procedure would change the formula you use to calculate your ppm of SO2. Using the large formula for calculating Free SO2 content, listed in the manual (currently on page 6 of the SC-100A manual) your value for ‘S’ would change to 10mL of your wine sample (where normally this is 25mL). And then you can proceed with the calculation of the equation. You will not be able to simply use the 20*V calculation.

Here is the full equation:                                    ppm SO2 = (64*V*N*1000)/2*S  (listed in the manual)

For example: If you use a 10mL wine sample (S), perform the test and you use 3.5 mL of your SO2 Titrant (V), the equation would look like this:

ppm SO2 = (64*3.5*0.0156*1000)/2*10              =             174.72 ppm Free SO2

*When adding DI water to your wine sample, do not worry. This will not affect your SO2 values. Adding this water allows you to bring up your sample volume to a more manageable volume but will not affect your SO2 readings.

Here is a study we did comparing the SC-50 to other methods. We get results that agree with standard analyses using very expensive equipment!

Vinmetrica’s instruments correlate very well with other methods

Very high alcohol levels may change the response of the system somewhat. The boiling step generally reduces levels far enough to limit this problem. For very high alcohol levels, you can dilute the wine in distilled water to bring the concentration below 10% ABV.
High free SO2 levels (>30ppm) may impact the Biopressure agent. Again, boiling will help this, but if needed you can dilute the wine sample as above.

Timing in this step is not critical but needs to be as close to the 45 minute mark as possible. Accuracy of the technique may be affected by letting the reaction go for excessive periods of time.

Check to be sure the insertion needle is not plugged or partially obstructed.

a) Disconnect the needle assembly as shown in Figure 2 of the manual.
b) Draw back the plunger of the 5 mL syringe and connect the needle assembly to the syringe end.
c) Push the syringe plunger to force obstructing material out of the needle. Check for free flow by suspending the needle in water while pushing the plunger. A steady stream of bubbles should flow easily out the end of the needle. You can order replacement needle/assemblies from Vinmetrica (part number SC-50-15).

a) It is normal for values to decrease slowly; that is why we recommend taking the initial highest value.
b) If values keep increasing past about 5 seconds after the insertion event, take a reading at the same time point (15-20 seconds later) for all samples.

Temperature can have a significant effect on the assay. The recommended temperature is standard room temperature, or about 70 °F (21°C). Temperatures within 3 degrees °F (or 1.5 °C) of this value should be fine. At lower temperatures, the rate of the Biopressure reaction slows down, and the pressure change also is lower, just like car tires lose pressure in cold temperatures. Therefore the assay is less sensitive at lower temperatures.

At higher temperatures, the opposite effect occurs: the reaction will go faster and generate higher values. In principle this is not bad per se – the assay becomes slightly more sensitive with the higher pressures generated. There is nothing wrong with using a higher temperature up to about 95°F (35°C), with two cautions: 1. the higher pressure resulting from higher temperatures may throw off the instrument’s 50 nA set point so it now will signal at a level below the 0.1 g/L level – therefore you will have to pay attention to concentration calculations; 2. most users’ environments aren’t set up to control higher temperatures that well, so increased variability may result. A warm water bath with controlled temperature can be used.

After heating your wine sample for 90 seconds, as instructed in the manual, your sample should have approximately 7 to 8 ml of wine remaining.

Be sure and let it cool completely before bringing the volume back up to 10 mL!

Absolutely!

Yes! Though you will need to edit the calculations slightly.

Take a 1.0 ml sample instead of the usual 0.10 ml for wine analysis. The rest of the assay is carried out as usual. The final result [%ABV = (Vb – Vs)* 2.88] is divided by 10 because you took 10 times more sample.

Sentia Wifi connection

To connect your Sentia device to a wireless network, follow these steps:

1. From the Home screen, touch the SETTINGS button, then touch Connectivity to navigate to the Connectivity screen
2. Touch Wi-Fi Settings to get to the Wi-Fi Settings screen
3. Turn on Wi-Fi and press 
4. Select a network from underneath the CHOOSE A NETWORK panel and enter the Wi-Fi password (if prompted)
5. After the connection is established, press  to confirm your selection

   

To stop the analyzer trying to connect to a previously connected network, select Known networks on the Connectivity screen, then select the network by name and touch the rubbish bin icon.

Note: The Sentia analyzer only supports 2.4 GHz Wi-Fi (channels 1 to 11).  Routers using 5 GHz or 2.4 GHz channel 12 are NOT compatible with Sentia analyzers.

If you continue to have problems, change Wi-Fi signals to a network which has fewer other device connections (such as a mobile phone hotspot).

As of March 1, 2023:

Current Software Version: 2.2.0.460

How to locate software information on your Sentia device:

1. On your analyzer, tap Settings on the Home screen.

2. Tap About

3. Tap Analyzer Information

4. The software version that you are currently running is located on the Analyzer Information screen under Version.

Please ensure that you are always running the most up to date software version available.  Details on how to update your software version are provided here.

A step-by-step guide for updating software.

1. Connect device to a power source.
2. Connect device to internet.  The Sentia analyzer can only check for software updates when connected to internet (via Wi-Fi).
3. If a software update is available, an “i” for install will appear on the device Home screen, top left-hand side. *
   
4. Touch the “i” icon and permit the new update by pressing 
   

* Note: upon Wi-Fi connection it may take your device some time to recognize that a new software version has become available.

A step-by-step guide to completing a hard shutdown on your Sentia™ device

1. Turn on the device and do not connect it to power.
2. Hold the off button until the screen goes black (approximately 10-20 seconds).
   Note: ignore the prompt “Power Down?” from the device to shut down the device (do not press the tick, keep holding down the off button).
3. When the screen goes black, release your finger from the on/off button.
4. You may now turn it on again.

Wine sampling tips for the generation of accurate results on your Sentia™

Good sampling technique is important for achieving accurate results on the Sentia.  To collect a well representative sample of your wine, follow the below tips:

• Collect your sample from a homogenous area, i.e., the middle of a barrel, tank or bottle; do not skim the top or bottom.
• Degas carbonated samples *
• Do NOT hold samples in your pipette, or an alternative transfer vessel, for any extended period of time.  It is recommended that samples be tested as soon as possible post-collection; immediately for free sulfur dioxide (FSO₂) testing.

*  Note: Heavy degassing procedures are not applicable to FSO₂ samples.

Best practice for obtaining your grape juice sample from the vineyard.

To obtain a good grape juice sample – as representative of a final must as possible – follow the below steps:

• DO collect a decent sized number of FRESH grapes for juicing (with clean hands) – 100 recommended where possible, to be taken from multiple bunches, top/middle/bottom.  Remove stem and leaf matter.
• DO collect grape bunches from randomized locations within the vineyard for best representation of your overall harvest.
• DO sample in the cool of the morning, before any moisture stress occurs.
• DO NOT collect grape bunches from exterior vineyard rows (border rows or end vines) or from other sites with unusual features. E.g., rocky or poor drainage areas. This will minimize the risk of contaminated or skewed results.
• DO NOT collect grape bunches from any diseased or damaged plants.
• Crush sampled grapes in a zip-lock bag (double-bagging is a good idea to avoid any leakage issues).
• Test juice as soon as possible (or refrigerate*).  Do not leave juice to ferment as this will impact your results.

* Long term refrigeration is not recommended; 1-2 days storage is acceptable.

How to get the most out of your micropipette

The micropipette, if used correctly, is a fabulous tool for taking small volumes with great accuracy.  For best technique, consider the following tips:

• Make sure your pipette is in good condition, and gets regularly calibrated (refer to your owner’s manual for suggested time intervals)
• Choose the right pipette for the right job. E.g.  For the Sentia device, a 100-1000 µl (0.1 mL – 1 mL) micropipette is adequate for the volume range to be covered.  DO NOT use a pipette past its volume limits.
• DO use the correct pipette tips for your device and avoid roughly jamming them onto the pipette tip cone.  Jamming tips on can break the shaft.
• DO keep your pipette clean to avoid contamination issues.  Most pipettes can be cleaned externally with typical laboratory cleaning agents, soap or alcohol (refer to your owner’s manual).
• Learn your plunger stops and good technique (stop 1 is used for aspiration/uptake and stop 2 for dispensing). *
• Practice using your pipette, ideally on water, prior to a first-time testing event.

* Correct pipetting technique instructions covered here.

Sentia results can be compared with alternative method results, or a wine “standard”, to confirm accuracy.

If you’re unhappy with a result generated by the Sentia device there are a number of things that you can do to check its performance:

• Re-sample and retest.  Sampling errors can cause erroneous results (for sampling advice please refer to articles such as How to Collect a Wine Sample and How to ensure accurate free sulfur dioxide results).
• Validate the result via an alternative method.  This can be done in-house or externally via the use of a commercial laboratory.
• Measure an in-house wine “standard” of known concentration on Sentia – e.g., a wine sample that is part of an organized proficiency program.

Things to remember if comparing results with another laboratory and/or method:

• Different methods will always give slightly varying results due to different error margins.
• For an accurate comparison, the User MUST sample from the same aliquot originally tested.

How to troubleshoot malic acid result issues

Malic Issues

Possible cause one:
Ensure you are conducting the sample dilution step correctly. The dilution should be conducted with a volumetric pipette, and always follow a 1:4 dilution ratio with the Sentia™ malic acid buffer. The analysis should be conducted within 30 minutes of diluting the sample.

For further information on how to perform a malic acid dilution, please read our Guide to sample preparation for Sentia analysis or watch Preparing Diluted Samples for Sentia Analysis. 

Possible cause two:
The malic acid buffer and/or strips are out of date or have been compromised. Ensure that they are in date and have been stored correctly (2°C – 8°C/35.6°F – 46.4°F, with lids closed).

Possible cause three:
The customer is running on an old version of software which is no longer compatible for malic acid analysis. See our current software version here.

Customers can check their current software by navigating to Settings > About > Analyzer Information. The software version number is listed under “version”.

Possible cause four:

Your reference method data is incorrect, as opposed to your Sentia data.  Recheck your reference method result, and/or employ a different check method for comparisons.

A step-by-step guide for analyzing fructose on the Sentia™

To test for fructose on the Sentia you will need to dilute your sample 1:4 (1 part wine: 4 parts fructose buffer).

Equipment and solutions required:

• Sample (wine)
• Sentia Fructose Buffer (diluent)*
• 1 x small, clean vial
• Micropipette
• 2 x clean micropipette tips

Dilution instructions:

1. Using a micropipette with clean tip, accurately pipette 400µl (your 4-parts) Sentia™ fructose buffer into a clean vial.

2. Dispose of the used tip and replace.

3. Accurately pipette 100 µl (your 1-part) wine sample to same vial.

4. Dispose of pipette tip.

6. Cap vial and gently shake to mix (highly carbonated samples may need a de-gassing step)

7. You now have a diluted wine sample ready to use. (Note: samples can be diluted for up to 30 minutes prior to testing)

8. Dispose of waste wine and buffer solutions down the sink with running water.

* Alternative buffers should NOT be used.  Please also refrain from combining buffer solutions from different bottles to avoid changes in the buffer concentration and check expiry dates before use.

For further information on how to perform a fructose dilution, please read our Guide to sample preparation for Sentia analysis or watch Preparing Diluted Samples for Sentia Analysis. 

How to troubleshoot sugar result issues

Glucose Issues

Possible cause one: 

The glucose strips are out of date or have been compromised.  Ensure that they are in date and have been stored correctly (2°C – 8°C/35.6°F – 46.4°F, with lids closed).

Click here to access the most up to date Sentia expiry information.

Possible cause two: 

Excessive CO₂ present in sample.  All samples with visible effervescence should be degassed prior to testing.  If not degassed, bubbles can cause sample-electrode contact issues and lead to erroneous results.

Possible cause three:

Sample excessively high in glucose, far exceeding the measuring range of 0.1 – 10 g/L.  This test is designed for dry style wines as they near fermentation end.  Testing samples with extreme sugar levels can lead to erroneous results.

Fructose Issues

Possible cause one:

The fructose buffer and/or strips are out of date or have been compromised. Ensure that they are in date and have been stored correctly (2°C – 8°C/35.6°F – 46.4°F, with lids closed).

Click here to access the most up to date Sentia expiry information.

Possible cause two: 

As per above for Glucose, cause two.

Note: excessive CO₂ for fructose samples can also impact upon dilution accuracies. CO₂ can displace sample in a transferal process, leading to lower than required volumes being aliquoted.

Possible cause three:  

As per above for Glucose, cause three (fructose with same measurement range).

Possible cause four:

The sample dilution step is not being completed correctly.  The dilution should be conducted with a volumetric pipette, and always a 1:4 dilution ratio with the Sentia fructose buffer.  The analysis should be conducted within 30 minutes of diluting the sample.

For further information on how to perform a fructose dilution, please read our Guide to sample preparation for Sentia analysis or watch Preparing Diluted Samples for Sentia Analysis. 

A step-by-step guide for analyzing malic acid on the Sentia™

To test for malic acid on the Sentia you will need to dilute your sample 1:4 (1 part wine: 4 parts malic acid buffer).

Equipment and solutions required:

• Sample (wine)
• Sentia Malic Buffer (diluent)*
• 1 x small, clean vial
• Micropipette
• 2 x clean micropipette tips

Dilution instructions:

1. Using a micropipette with clean tip, accurately pipette 400 µl (your 4-parts) Sentia malic buffer into a clean vial.

2. Dispose of the used tip and replace.

3. Accurately pipette 100 µl (your 1-part) wine sample to same vial.

4. Dispose of pipette tip.

6. Cap vial and gently shake sample (highly carbonated samples may need a de-gassing step)

7. You now have a diluted wine sample ready to use (Note: samples can be diluted for up to 30 minutes prior to testing)

8. Dispose of waste wine and buffer solutions down the sink with running water.

Alternative buffers should NOT be used.  Please also refrain from combining buffer solutions from different bottles to avoid changes in the buffer concentration and check expiry dates before use.

For further information on how to perform a malic acid dilution, please read our Guide to sample preparation for Sentia analysis or watch Preparing Diluted Samples for Sentia Analysis. 

Tips for getting an accurate free sulfur dioxide reading on the Sentia™

Sentia User’s must be mindful that free sulfur dioxide (FSO₂) is a highly volatile compound, sensitive to oxygen and oxygen binding events.  This means that FSO₂ samples need to be collected with particular care and tested rapidly for best results.

Tips for FSO₂ sampling:

• Collect a homogenous sample (as outlined in How to take a wine sample)
• Collect a decent sized sample; DO NOT transfer/apply miniscule or bubbled volumes to your Sentia device.  Over aerated samples can lead to lower than true figures.
• Test FSO₂ samples IMMEDIATELY post-collection where possible.
• If you cannot test your FSO₂ sample immediately (or you’re conducting a comparison with another FSO₂ method), store the sample in a sealed vessel containing little to no air until use.
• DO NOT test FSO₂ with the Sentia device (or any other device) immediately after making any SO₂/PMS additions to your wine.  The wine will need at least 24 hours after a dosing event to settle and re-stabilize before testing.
• DOT NOT test FSO₂ on highly carbonated samples.

Figure 1. Dos & don’ts for FSO₂ sample collection. 

Figure 2.  Dos & don’ts for FSO₂ sample storage.

Sentia™ degassing instructions

Highly carbonated samples may require a small degassing step prior to testing.

The sample should be placed into a small container and shaken vigorously for ≥ 20 seconds to displace gas. Ensure that the sample container is only filled up part way to allow for sufficient agitation.

Consider further degassing measures if results are not as expected.

Note: It is NOT recommended to degas samples prior to Free sulfur dioxide (FSO₂) analysis.  Highly carbonated samples are not suitable for FSO₂ testing on the Sentia.

We always recommend checking your local regulations as they vary depending on where you are.

The small amount of formaldehyde in a YAN test is neutralized entirely by following the procedure in the manual, and since the pH of the solution should be less than 9 at that point, there should be no problem in sewering the test’s contents.

We offer quality laboratory testing for brewers and winemakers. We believe our clients should be guaranteed that their samples are handled with the utmost care and to the highest standards. Our laboratory services will be performed following the rigorous AOAC and TTB approved wine and beer analysis methods.

We try to minimize our changes in price for our laboratory services as much as possible. But the laboratory service prices can vary from time to time depending on the time of the year. All reports are strictly confidential and are meant for client’s use only. Our prices on our website reflect our up to date pricing.

Note: We are not responsible for wine samples that are improperly packaged, damaged or deteriorated during their shipment. Please contact us if you have any questions or concerns regarding shipping and handling. Our contact email: info@vinmetrica.com and our technical support and sales phone number is (760) 494-0597.

Shipping Preparations for Beverage Samples

Note: We recommend that you do not ship samples on Friday or Saturday as the samples could be compromised over the weekend due to deterioration of the sample. If shipping Thursday, make sure to ship via overnight, so the samples do not sit over the weekend.

1. Upon receiving your Vinmetrica Labs sample shipping kit, please place the gel pack in the freezer for 12 hours or until the gel pack is frozen solid.

2. Prepare the sample by filling up either the 15 mL or 50 mL conical tube then cap and seal tightly. Look on the Vinmetrica Labs Label for a Min. Volume necessary for that specific test.
Note: Fill the conical tube to a level above the beginning of the threads near the top of the tube to reduce headspace. (this is a volume either over 15mL or 50 mL depending on the size of the tube)

3. Fill out the Vinmetrica Labs label that is provided. Check the box for the test that you wish to be performed on your sample. Please include a phone number and an email address on one of the labels. Place the label on the tube so the label is not overlapping itself.
Note: One analysis per tube. Please only check one box per conical tube. Analyses require a certain volume which will be either the 15 mL, 50 mL or 100 mL Min. Volume category. For 100 mL analyses, please fill two 50 mL conical tubes as per the instructions above.

4. Repeat steps 2 and 3 for all sample analyses ordered.

5. Place the samples in the ziploc bag provided and seal shut. Place the ziploc bagged samples and the frozen gel pack into the styrofoam box.

6. Place the prepared styrofoam box into the cardboard box that is provided. Tape and seal the box closed. Print out a shipping label addressed to us (our address is below) and please write on the label, in a conveniently readable location, “For Laboratory Analysis Only”.

Note: The shipping supplies are provided free of charge. Expect arrival in 3-4 business days for handling and delivery of the supplies.

For Local Drop-off

If you are near North County San Diego, feel free to stop by and drop off your sample Monday through Friday 9-5pm. Our address is:

Vinmetrica

6084 Corte Del Cedro, Suite 105

Carlsbad, CA 92011