pH meter sample question

I suspect that this is to reduce the possibility of contamination of your must. The pH meter tip may still be wet with storage solution, or, if you've rinsed it with tap water, it may be harboring microbes.

It's just better not to stick anything into your must.

Greg

snpm wrote:

I also take a sample of the must but I'm usually doing both a pH reading and an acid titration. I usually dilute a 1 mL sample in about

1 oz. of hot (microwaved) distilled water to drive off CO2 gas. When cooled I put the pH meter in to get a reading then proceed with the titration to an end point of 8.2. Distilled water has virtually no buffereing capacity - the dilution does not change the pH reading.

RD

........erm, I find the logic hard to swallow if its just that, dont you? Why wouldnt you simply sanitise the instrument? You have to stick SOMETHING in the must to get the sample, right?

snipped-for-privacy@testeng> I suspect that this is to reduce the possibility of contamination of

I normally use straws from fast food restaraunts as wine thiefs. They are extruded at high temperature and almost immediately enclosed in a paper or plastic wrapper. As such, they are unlikey to be a source of contamination. I draw out a few teaspoons into a wine glass and place the pH meter in the sample.

You could, I suppose, sanitize the probe tip in a sulfite solution, but it is a sensitive instrument. I would rather just expose the probe to storage and calibration solutions, and to the must.

There's nothing to be gained by placing the probe directly into the must, and since there are some possible risks, why bother?

Greg G.

yeah makes sense. Thanks Greg ..!

snipped-for-privacy@testeng> > ........erm, I find the logic hard to swallow if its just that, dont

not to mention the crusher/press cross-contamination lolol

The reason for not putting the pH probe in your must is to not risk getting pH electrode chemicals in the must, if you should happen to have an oops. And to not get glass fragments into the must from that oops. This is just common sense good practice.

Gene

P.S. Older pH electrodes often contain calomel (mercurous chloride), which is something we don't want to ingest. Most pH electrodes made today use AgCl (silver chloride) electrode instead of calomel.

P.P.S. Last I checked, no microbes that will harm us can live > ........erm, I find the logic hard to swallow if its just that, dont

Don't forget acetobacters. They could produce an unpleasant surprise.

Greg

Thanks for calling them to the fore. Those acetobacters go overboard. Yep... I include those in the 'fart bad tastes' in the context of wine.

Many here may not know it, but even our beloved wine yeasts generate small amounts of acetic acid as a fermentation by-product. Interesting, too, that at low concentration, some of the bad tastes can add interest to wine. That includes acetic acid, as long as it's not much above the threshhold of taste.

Gene

You are absolutely correct. Wine geeks often refer to "barnyard notes" on the nose of many Pinot Noirs. I mentioned this to some non-winedrinkers a while back and they thought I was crazy. It's hard to imagine how anything sensed in a wine could be compared favorably to a barnyard.

Greg G.

I accept the received wisdom, but has anyone actual evidence of 'properly' sanitised equipment causing these problems? It sounds to me like the problems are caused by inproper precautions rather than necessary problems. Forgive I my newbiness.

Jim

Equipment sanitation practices aren't the only contributors to oddly described flavors in the wine. Many of them come in with the grapes.

For example, I know of a zinfandel that got overpowered by eucalyptus flavor, where the eucalyptus oils landed on the grapes from nearby upwind trees.

But barnyard overtones (aka Brettanomnyces) is a winery sanitation artifact for sure.

Gene

jim wrote:

sanitised equipment causing these problems?

than necessary problems. Forgive I my

sanitised equipment causing these problems?

than necessary problems. Forgive I my

Jim I would never put my probe in my wines, I always pull a sample. I have a Hanna PHeP5 and there is no way you can clean that assembly well and I would not want to risk damaging the probe either. I do 50ml samples; it's not a big deal to me. I'm not saying things crawl out of my pH meter, just that it's not something i would swirl in a glass of water i was going to drink...

Are you sure it's even a good idea to sanitize a pH meter probe? They are pretty delicate.

Joe

There are several Shiraz from Australia that have a hint of eucalyptus. The winemaker's usually explain this as being caused by decomposing eucalyptus leaves in their vineyards; eucalyptus becomes part of the terroir. Perhaps that just seems more palatable than having trees drip sap on your grapes.

Greg