*Please note that these are guides, summaries of the procedure, and should not be used in place of the full manual. For your first use, please refer to the full manual. *
Frequently Asked Questions
Vinmetrica’s Return Policy:
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 email@example.com or call +1 760 494 0597 and select Tech Support, with any questions.
Vinmetrica’s warranties and liabilities are:
1. The materials provided in the kit, as described on pages 1 and 2 of the Kit Manual, (“Materials”) are warranted as follows: Instruments, electrodes and non-reagent accessories are warranted against defects in workmanship for 12 months from date of purchase. The reagents are warranted to perform as described in the manual up until any stated expiration 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 6 months, and we now give an expiration date that should be a minimum of 12 months from purchase. To ensure best stability, always store tightly capped. And of course, the reagents will last much longer if not cross-contaminated with each other!
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.
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|
No, don’t worry, your pH meter should still work. To fix it, leave your pH electrode in the pH 4 calibration solution for an hour and it should return to normal function. Enabling SO2 mode with the pH electrode attached could cause the pH electrode to wear out more quickly. Because of its design, SO2 mode cannot be accessed unless you press ‘enter’ after pressing the ‘mode’ button, this is another safeguard we installed to prevent this from becoming a problem.
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.
The SC-100A is simply a new body style using the components found in the SC-200 and SC-300. It functions exactly the same, with only the audible buzzer slightly different in its tone. The reagent kits for the SC-100 and SC-100A are the same. While we no longer sell the SC-100, we still support it, and will continue to do so.
The Acid solution is 2M (2N) Hydrochloric Acid (HCl) (6% W/W). The solution is considered a hazardous material. For the international units or reagents, we have found an acceptable method of shipping with FedEx. This is in compliance with international shipping standards. We can now ship the acid solution internationally. The acid solution will arrive in 1 ounce bottles but will function the same. This restriction also applies to shipments destined for Alaska and Hawaii.
This information does not apply to international shipments to Canada or Mexico.
If you are interested in purchasing the large 450 mL volume bottles of the acid solution or the SC-100 & SC-300 SO2 Reagent set, please email firstname.lastname@example.org for more information.
ALWAYS use caution when dispensing or diluting the acid solution. It is not terribly dangerous but ALWAYS use laboratory protective eyewear, gloves and preferably long sleeves, pants and closed toed shoes. If you do happen to get it on you flush with large amounts of water. If the acid solution gets into the eye, walk over to a sink and flush water in your eye for 10-15 minutes, call 911 if there is any concern and consult a poison control agency, in the US call 1-800-222-1222. For poison control in other countries check out this website. Poison Centers.
Another option for getting a large amount of the acid solution would be to order 2M HCl from Sigma Aldrich, click here. You can order a liter of 2M HCl through them, while on the website it claims it is 22.70 per liter, there is also an added $15 – 25 hazardous materials charge and then the shipping cost on top of that. So the cost is from $37.70 – $47.70 plus shipping. At Vinmetrica, each SO2 analyzer kit has 100 mL of the 2M HCl Acid reagent which is good for about 50 tests, so you can imagine that you will not run out of the liter quantity anytime soon. HCl almost never deteriorates (as long as it is not cross-contaminated and is stored and sealed properly).
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:
The SC-100 has a voltage drop of about 0.5 V , so a good battery will generally read about 8.5V. In fact the SC-100 will still function when the battery is well below 8V, though we recommend replacing the battery when the battery check warns you with its red LED and buzzer.
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.
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.
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: email@example.com and our technical support and sales phone number is (760) 494-0597.
We send shipping supplies to you, free of charge, once you place your order.
Please make sure to send us your samples in a tightly sealed container per the “Wine and Beer Sample Shipping Preparation” instructions. Be sure to mark each sample, marking such as “Merlot A” or “Merlot B” are sufficient as long as you know which sample is which. The more detail the better.
*If you are sending an entire bottle, please let us know in the Customer Notes section during checkout.*
The Shipping Supplies includes everything below, with the number of tubes and size of the box based on how many tests you purchase:
• Cardboard box for returning the shipment
• 50mL or 15mL conical tubes (one for each analysis or two if the analysis requires a 100 mL sample)
• Vinmetrica Labs Conical tube labels
• Gel pack and Styrofoam container (for certain sample analyses, if sample requires being kept cold)
Once you have prepared your sample from the ‘Wine & Beer Sample Shipping Preparation’ instructions, make sure to attach a shipping label to the top of the cardboard box and ship to the address below. Please write on the box “For Laboratory Analysis Only”.
If you are near North County San Diego, feel free to stop by and drop off your sample Monday through Friday 9-3pm (please drop samples earlier in the day so they can be processed in a timely fashion). Our address is:
6084 Corte Del Cedro, Suite 105
Carlsbad, CA 92011
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
We have distributors in the US, Europe and Canada
Interested in becoming a distributor or need additional information?
Please contact Taylor at firstname.lastname@example.org
In the US
Australia & New Zealand
We ship to Canada via FedEx Ground. Vinmetrica does not pay for any duties, taxes or fees that are applicable upon entry but all freight charges are included. Click here to return to our North American Products page.
If you would prefer, you can purchase one of our products through our Canadian distributors. Click on the link above for a list of our distributors.
If you are outside North America we must ship the acid reagent, 2M HCl (2N HCl) found in the SC-100A & SC-300 analyzers, the Pro Kit and the SC-100 & SC-300 SO2 Reagent kit in small 1 ounce bottles because of hazardous materials restrictions imposed by international shipping standards. This does not change the function or concentration of the acid solution and you still use 2 mL of the acid solution for each Free SO2 test.
If you are purchasing the large 450 mL volume bottles of the acid solution or the SC-100 & SC-300 SO2 Reagent set (these large replacement bottles which are sold separately from the units themselves), the acid solution will arrive in small 1 ounce bottles as well.
Similarly, we must ship the 100 mL of 1M (1N) NaOH solution in 1 ounce bottles (an optional item for doing Total SO2 analysis – not included with the analyzer or reagent kits) when ordered internationally because of these hazardous material restrictions.
Another alternative shipping method is to contact one of our distributors. If one of our international distributors is close to your location, we can get you in contact with them. Feel free to email, email@example.com, or call us, if you have any questions regarding international shipping. We are available Monday – Saturday, 9am – 5pm PST: +1 (760) 494-0597
For more information on the Acid reagent check out the link below.
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)