Testing equipment

I work for a smallish winery (about 3000 cases annually) and we are looking for some recommendations for equipment for testing our alcohol levels (after fermentation) and free SO2 without sending samples out to a lab or setting up a lab ourselves. Is there small/portable meters out there that we can use for these purposes? I would appreciate any recommendations you might have. Cheers!

I kind of depends on how much you want to spend, but if you are small, I’d imagine you want to not have to spend a lot. As for portability, well, not so much.

For alcohol, your least expensive option short of an old school ebulliometer, is an electric ebulliometer.
Some people claim you can use refractometers for alcohol determination, but there are several impediments to getting accuracy with them. One being you have to have a very accurate Brix reading before fermentation. Things that can get in the way of that are spontaneous early fermentations kicking off before accurate reading is taken, and also water additions. If you water back at all, getting accurate measurements is very difficult until you have done several pumpovers, and by that point your fermentation may be starting. Also, when your must gets below ( Brix, the measurements get wildly inaccurate. One of our interns did a comparison study between Anton Paar/ refractometer with calculation a couple of years ago and 9 Brix seemed to be the across the board failure point for the refract.

When I popped into Vinquiry a couple of years ago they had a new gadget they were pushing, but I think the method was based on the ebulliometer method, but don’t quote me on that.

As far as FSO2, your easiest quick-and-dirty method is Ripper, although accuracy is not great. But if you have one person running the test, you should get good precision at least. This is also the least expensive option. If you want to get better accuracy with only a bit more expense in glassware, I would suggest A/O. This takes longer than Ripper, but at a small winery ten minutes per test probably isn’t prohibitive.

FSO2 is the one measurement that has not really improved much over time. You can run them on Mettler Toledo titrators (TA models with add-ons), but it is still based on the Ripper method. You can run them enzymatically, but specs are expensive. I’ve seen some other gadgets out there that make big claims, but they really are not great.

Hope that helps.

I use this, made by a company called Vinmetrica -

It basically turns SO2 tests into a titration which is pretty easy to do and to me, easier than AO method. We are even small production than you but we are very close to ETS labs. We send samples for alcohol to them since it usually isn’t time critical. Brix, TA, pH, SO2 capabilities is all we have in-house but we’ve found that this is all we need.

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I use the Vinmetrica tester for SO2 and TA (and pH). The unit has some other capabilities, but I don’t have the patience for their more testing procedures. SO2 and TA are relatively simple, but I get enough variation in repeated tests on the same sample that I generally have to average out at least a couple measurements.

Curious about the vinmetrica equipment and ‘calibrating it’ to ETS or another lab - do you run concurrent samples and note differences in any?

The way I look at Ripper is that it is great to give you an idea of whether you have much if any Free SO2 but the actual number will vary perhaps up to 7-8 ppm from A/O . . .

Cheers.

For FSO2 just get an AO setup. I don’t care for Ripper… ajd I absolutely don’t care for all those Mickey Mouse gadgets. They’re barely as accurate as a ripper.

Alcohols? Just send out. ETS is $26/sample… and you only need an alcohol 2-3x during its life on average.

Well I wouldn’t assume AO is 100% accurate, I thought it was expected to measure slightly high in red wine. I sampled my own numbers with tests from ETS and found them within 4-5 ppm of each other. Maybe AO is more accurate but I’m realistic about what I’m willing to do. A test that is easier to do is more likely to be done in a timely manner. We are a very small operation, if I had 50 samples and a dedicated lab tech, then I would consider other options. The Vinmetrica seems well made, IMO, far simpler and better quality than machines from Hanna which are also in the small operation price range.

I’m a micro producer using Vinmetrica SO2 testing for 7 years. It is easy to learn and perform, which as Steve said makes for less procrastination.

I recommend getting a buret to accurately titrate, however, as using a syringe is tricky. Also using fresh solutions as always.

Here is a comparative study showing good accuracy: