Vinmetrica’s Return Policy:
Customers are entitled to a full refund less a restocking fee of 15% will be charged on all returns made within 45 days of shipment, unless items are returned for repair or warranty service. ALL returns must be sent with a valid RMA number which we will assign to your item after you contact us.
If you believe that you have defective equipment we will work with you to resolve the issue and repair or replace once a diagnosis has been completed. Please contact firstname.lastname@example.org or call +1 760 494 0597 and select Tech Support, with any questions.
The SC-100A, SC-200 and SC-300 units each come with a 2 year warranty. Any electrodes come with a 1 year warranty and all plastics, lab equipment and reagents come with a 6 month warranty.
While the reagents only have a 6 month warranty (this is because we do not know how the reagents are treated once they leave our hands), with proper care most of them should last at least two years. All reagents have a use by date clearly printed on the labels.
Vinmetrica’s warranties and liabilities are:
1. Instruments, electrodes and non-reagent accessories are warranted against defects in workmanship for 24 months from date of purchase. The reagents are warranted to perform as described in the manual up until any stated expiration or “use-by” date, or 6 months after purchase, whichever is later. THE WARRANTIES IN THESE TERMS AND CONDITIONS ARE IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT, OR FITNESS FOR A PARTICULAR PURPOSE, SAID WARRANTIES BEING EXPRESSLY DISCLAIMED.
2. Buyer agrees that its sole and exclusive remedy against Vinmetrica shall be limited to the repair and replacement of Materials or parts of Materials, provided Vinmetrica is promptly notified in writing, prior to the expiration of the warranty period specified above, of any defect. Vinmetrica’s liability for any damages due Buyer shall be limited to the purchase price of the Materials.
3. VINMETRICA’S MAXIMUM LIABILITY FOR ALL DIRECT DAMAGES, INCLUDING WITHOUT LIMITATION CONTRACT DAMAGES AND DAMAGES FOR INJURIES TO PERSONS OR PROPERTY, WHETHER ARISING FROM VINMETRICA’S BREACH OF THESE TERMS AND CONDITIONS, BREACH OF WARRANTY, NEGLIGENCE, STRICT LIABILITY, OR OTHER TORT WITH RESPECT TO THE MATERIALS, OR ANY SERVICES IN CONNECTION WITH THE MATERIALS, IS LIMITED TO AN AMOUNT NOT TO EXCEED THE PRICE OF THE MATERIALS. IN NO EVENT SHALL VINMETRICA BE LIABLE TO BUYER FOR ANY INCIDENTAL, CONSEQUENTIAL OR SPECIAL DAMAGES, INCLUDING WITHOUT LIMITATION LOST REVENUES AND PROFITS.
The SO2 reagents and the pH/TA reagents are all warranted to last for 1 year, and we now give a use-by date that is 2 years from date of manufacture; in fact generally all SO2 and pH/TA reagents can be used several months beyond the use-by date. To ensure best stability, always store tightly capped and out of high temperatures and sunlight. And of course, the reagents will last much longer if not cross-contaminated with each other!
If there are segments of the LCD display that no longer illuminate or whole numbers have disappeared there is probably an issue with the LCD screen itself. Most often, a replacement LCD screen can be installed and this fixes the issue. Typically, when the LCD screen goes out the instrument will still work okay. If this has happened to you, please call or email our tech support for an RMA number and we can give you additional instructions.
Sometimes, although rarely, there are other issues with the circuit board that cannot be fixed. If this is the case, the unit will need to be replaced.
If a repair/replacement is needed and the unit is out of warranty there are costs associated with these services. The units are covered under a 2 year warranty. If it is out of warranty the cost of the LCD screen replacement is $75 plus return shipping.
There is no major difference between the two sizes of burettes besides the difference in capacity. We recommend the 25mL burette if you will be doing multiple tests in a row as the larger capacity allows you to run multiple tests without having to refill the burette with Titrant. The 10mL burette is slightly more accurate as the gradations on the burette are finer so you can read it to one additional decimal point.
The most popular is the 25mL burette although the 10mL is also a good option too. It is just whichever you prefer.
If you think you may want to do the ABV Assay or the RRS Assay in the future you may want to purchase your Pro Kit or Deluxe Lab Kit with the 10mL burette as those two assays require the 10mL burette in order to get accurate results. Or you can simply purchase an individual 10mL burette at a later time.
If the connector itself is loose and can be pulled out of the housing then the instrument will need to come back to us for repair (if it is still under warranty). If it is out of warranty, please call us and we may be able to direct you on how to fix this.
If indeed you have the older RCA plug (gold connector), it sometimes fails to make good contact with the receptacle at the outer grounding ring; in that case try squeezing the outer grounding ring on the plug by ever so slightly compressing it with a pair of pliers. More information about this can be found on our Troubleshooting Guide on the Support tab.
The SO2 reagents included in the SC-300 should allow you to perform about 50 SO2 tests
The TA Titrant should be enough for about 30 TA tests.
The pH Reference Solutions should be good for an unlimited amount of tests. If you are careful enough and rinse your electrode well, you can simply place the pH probe straight into each of the reference solution bottles to calibrate. Make sure the solution is mixing at all times.
All these reagents have a 2-year shelf life.
Distilled or DI water are okay to use. Make sure they are fresh too.
Our full distributor list can be found on our “Find A Distributor” page.
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.
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.
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).
PH Variation with Temperature
|Temperature °C||Temperature °F||pH|
|pH 3 buffer (phthalate)||0||32||2.91|
|pH 3.49 check solution||5||41||3.47|
|pH 4.01 reference solution||0||32||4.000|
|pH 7.00 reference solution||0||32||7.115|
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.
Be sure to always stir or swirl your solution when calibrating or measuring, i.e. do not let the electrode sit stagnant in the solution. You will get considerable errors in your pH measurements.
A better way to test the validity of pH calibration is to measure the pH of a saturated solution of cream of tartar.
- 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.
- 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.
- Decant or filter the solution off the solids if possible.
- 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’.
% 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).
This is a common occurrence with several explanations, any or all of which may be happening:
- 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!
- 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.
- 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:
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:
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 above in this section of the Website)
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 Ascorbic Acid 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.
Yes! You can do this to save your Titrant but always make sure you are putting it back in the correct bottle. Make sure you do not cross contaminate any of the solutions. If you are careful this is a great way to preserve your Titrant.
This is most likely an issue with cross contamination. If they are cross 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 only reason the Acid would turn yellow (or sometimes a lot darker) is if the Reactant solution came in contact with it. The chemical composition of the Reactant is designed to show 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 email@example.com .
It is very important that 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!
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.
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!
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.
Services Page FAQs
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: firstname.lastname@example.org 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:
6084 Corte Del Cedro, Suite 105
Carlsbad, CA 92011
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SC-100A & the SC-100
- Sensitivity: detects less than 2 ppm Free or Total SO2 in a 25 mL sample
- Accuracy: +/- 2 ppm Free or Total SO2
- pH range: 1.0 to 13.
- Accuracy: better than 0.02 pH unit.
- Autocalibrate on pH 3.00, 4.01, 7.00, 10.00
- TA mode: Accuracy: +/- 0.2 g/L Tartaric acid.
- Sensitivity: Detects down to 0.2 g/L Tartaric Acid
- Combines the specs for the SC-100 and SC-200
- Sensitivity: better than 0.04 g/L malic acid (3 mL sample)