Ok. I have spent the last 4 hours without good results. I have checked everything I can think of. Help!
I have done this many times and had to re-do tests. Usually, one or 2 do overs to get what seems to be good info. But this is a new one.
The peroxide in the impinger tube goes purple, like it should, then half way through the 10 min., it turns back to grey.
Has anyone seen this?
Does anyone know the cause? Solution?
Thanks!
I can’t help you but I do like this machine as an alternative to AO systems for SO2-
I’m presuming this is an aspiration method test? Are you having problems with measuring the free or total; or both?
Are you using a fresh peroxide solution?
Is it possible your free SO2 is extremely low? I believe no color change at all indicates 0 ppm. So maybe 1 or 2 ppm won’t sustain the color change.
Thanks for the replies.
The problem is inconsistent results on the same wine.
Fresh peroxide.
I think the issue is with vacuum not being steady.
I’ll check out that tester. What does it cost per test, and how long does each test take?
They estimate 50 tests per set of reagent at $35, so $.70/test. Time is comparable to an acid titration. You lose the 10 minutes of waiting in AO. For me, I’m finding I’m doing a better job of tracking SO2 since it only takes minutes to do whenever sampling a barrel. Of course the cost savings over an auto titrator is based on you already having things like stir plates, burette, and stand. These aren’t absolutely necessary but make the job really easy. And most people have these already.
That would be my guess, although if you are seeing it bubble through, I can’t imagine that would happen. How vigorously is your peroxide solution bubbling?
Thanks for looking at this.
I have done lots of these and always been able to get good results that are consistent if I repeat.
It seem difficult to describe how much it is bubbling in a way that is meaningful. On the wine side, it is bubbling vigorously, to the point of some bubbles being on top on the wine.
The peroxide is bubbling vigorously as well, but less so, since the size of the bubbles is larger.
I think I need an adjustable vacuum pump, or a vacuum regulator to go on the sink aspirator. Any ideas on where to find that sort of thing at a reasonable price?
Alternately,
Has anyone else replaced sink aspirated AO with one of these? http://www.vinmetrica.com/products.html
Thanks again.
i’ve run into this problem - how old is your indicator?
Indicator, and or your 3% would be something I’d consider refreshing.
Thanks for your comments. I honestly don’t think indicator age or 3% age can explain why the test works one day and then the next day not at all. Which is what happened. I got what I believe are good numbers on all but one wine on the first day. I was looking at the results and one was not consistent with where I thought it should be. So, I re-did that one. This is when the test seems to show no result, but keep in mind what I am seeing. The solution starts gray, turns purple, then goes gray again.
Sorry I didn’t describe it in more detail earlier.
I would check the tubing setup, over time it can develop leaks, and if any liquid is aspirated into it, or the flowmeter, you can start to see variations caused by residues, etc. Taking it apart and soaking the tubing to clean it out takes some time, but a little cleaning and reassembly can make a big difference.
Brian Maloney
DeLoach Vineyards
Does anyone else use one of these?
Any issues to watch for with them?
How is it working with the people that make it?
Thanks again.
I bought the Hanna 84100 about a year or so ago and love it. The chemicals can get pricey, but depending on how often you test it might be very well worth it. I feel like the vinmetrica might not produce as you will demand with a little growth…and the chemicals will probably cost very close to what they do with the Haanna titrator.
Thanks for your suggestions. I have heard of the Hanna. The machine and the chems are both more costly. I suspect it is probably more accurate, but if the Vinmetrica works as advertised it would probably do for my use.
Anyone who has used the Vinmetrica? Used both?
My main question: does it work? and does it keep working?
I haven’t used the Hanna but looked at it for awhile before the Vinmetrica came out. Price per test is about 3x higher for the Hanna ($2.30 vs. $.70). But a bigger concern was that I heard several users saying that had to return the unit for replacement under warranty. It fairly complicated in that it has a probe, stir plate, pump, and electronics built together. The Vinmetrica has no moving parts and the display is simply a voltmeter, no analysis going on. Of course, its much easier to use with a stand alone stir plate but most have one anyway and they don’t seem to fail often. The probe is just two pieces of Platinum wire inside the case, nothing requiring calibration and it stores dry.
For me, a huge advantage for the Vinmetrica is speed. I typically only run 1 to 3 tests at a session. I can setup, test, rinse and put away in the time it takes for the Hanna to purge and calibrate itself (per Hanna video). Once setup, I think the speed per test would be the same but I would always spend more time setting up than using.
As far as accuracy, another user made comparisons to samples tested by Vinquiry and came within a couple ppm of the same figures. Considering there is no pump to calibrate, no wet probe, and no electronics, it might be more accurate than the Hanna. The test method itself appears very stable. I ran the same sample 4 times and found a variation of only 2 ppm.
I should point out that I am not a commercial operation. I’ve had mine for about 3 months and run around 20 tests, no problems so far. But of course this is not the same as hundreds of tests in a commercial setting.
Thanks for your detailed description. I am leaning towards giving it a shot. If I do, I will post results.
The Hanna does a Ripper analysis which is generally slightly less accurate than AO, but removing human error for the most part probably makes it a wash as far as accuracy is concerned.
I bought the Hanna a few years back. Had results that mirrored ETS for a bit, then starting getting false positives (Like 25-35 ppm when there was essentially less than 10 ppm). Sent the unit back to Hanna for the software upgrade/recall issue, and have had totally junk results from then on. The unit now takes up shelf space in the lab, as I have zero faith in its results. Back to the AO with occasional ETS cross checks. Don’t waste money on the Hanna unit.
Hi James,
Thanks for your post. I had heard mixed reviews of the Hanna, but had not yet heard such a clear and specifically bad report. Sounds like an unfortunate waste of $600. Sorry to hear that.
I’d consider going back to AO, but mine is sink aspirated. While my stepfather has gotten acceptable results with it for years, it is time consuming at best, and a serious time drain when trouble shooting is needed. I find it too difficult to replicate results and sometimes hard to get results that give me any faith at all. So, I could get a vacuum pump, but that is not cheap either. Even though I have not been able to get a second yes vote after Steve G’s good report on the Vinemetrica, I am thinking of rolling the dice on it.
Andrew,
After reading your post about sink aspirated AO I remembered last year when I ordered my AO unit they did not have an aspirator so I bought an aquarium pump for about ten bucks and it delivered just the right amount of air. I also found out that the pump works great for blowing out and drying pipettes.