should I pre-treat with bicarbonate?

If you're planning on making a sweet wine, you can balance that acidity with sugar -- even then you might want to bring it down a touch. If so, this might be a good candidate for just cold stabilization if that's easy for you, or a very small adjustment with potassium bicarbonate.

If you want to make a dry wine, you probably want to get the TA down to at least 0.75, and almost 0.25 reduction -- that's getting into the neighborhood of the largest adjustment you want to make with bicarbonate (I don't like to adjust over 0.20 TA with bicarb). Since you probably don't want to use a MLF, then bicarbonate, cold stabilization, or blending are your only options. Blending will have the least impact on the quality of your wine, but chances may be that you don't have a low-acid compatible white available to blend with. Cold stabilization is an option, but the maximum acid reduction you'll get won't touch the reduction you're looking for.

So, what I would do would be to aim for about half the acid reduction with bicarbonate prior to fermentation, and then test again after secondary fermentation. The first reduction will make the yeast happy, and you can wait to see what the fermentatio process leaves you with. At that point, you can make a decision based on taste as to if you want to reduce more by bicarbonate, try a cold stabilization, or even opt for a semi-sweet to balance the acid with sugar.

For each 0.10% TA reduction, I use the rule of thumb of 3.4 gm per gallon, but I only do half the adjustment, wait a day, take another reading, find the actual reduction, and replace the 0.10% TA in the equation with the actual reduction to calculate the remaining addition.

Jon [Check out my winemaking homepage

I agree with Jon, this looks to me like a good candidate for a wine with a little sweet reserve or residual sugar to balance the high acid

- though it's worth double checking your pH reading with fresh NaOH. My experience with Brehm juice is that it's usually pretty close to the advertised stats. Personally, I would not use bicarbonate at this point. I'd ferment cool (< 55F), cold stabilize after a bentonite fining, then let your taste tell you what it needs. You can always use bicarbonate later, if needed, but remember bicarbonate is only good at reducing tartaric acid.

Good luck, RD

I agree with Jon, this looks to me like a good candidate for a wine with a little sweet reserve or residual sugar to balance the high acid

- though it's worth double checking your pH reading with fresh NaOH. My experience with Brehm juice is that it's usually pretty close to the advertised stats. Personally, I would not use bicarbonate at this point. I'd ferment cool (< 55F), cold stabilize after a bentonite fining, then let your taste tell you what it needs. You can always use bicarbonate later, if needed, but remember bicarbonate is only good at reducing tartaric acid.

Good luck, RD

That sounds like underripe fruit to me. I had a similar situation to deal with in 1985 with Chardonnay.

The plus side is that you won't need much sulfite to prevent spoilage. The minus side is it's so acidic you could use it in your battery!

You could adjust now with potassium carbonate (NEVER sodium, and preferably not calcium), but it may yet go through ML and end up on the low side. Alternatively, you could wait until fermentation is complete.

I think the best course is to do a conservative adjustment now and another later if necessary. It's simply too difficult (if not impossible) to thread the needle at this point.

An addition of 2 grams/liter of KHCO3 sounds a little drastic to me. That would take your 0.98 TA down to 0.68 (after cold stabilization). After ML that number would be lower still. I suppose you could use lysozyme to inhibit ML, but there's still no good way of predicting where the pH would end up - ML or no.

If you adjust the TA of this juice (and I think you should), I'd recommend you go no higher than 1.4 grams/liter KHCO3. You really don't want to overshoot on this. You can hit it again later if need be.

BTW, the others who responded to your question gave you pretty good info too. I suggest that you weigh all of it.

Tom S

Hey,

FWIW, I wouldn't touch that acidity, at least not at this point. Our 2003 Reserve Riesling was harvested with a TA of 11.2 and a pH of 3.1, and bottled with 0.5% RS. TA of 10.3 (after cold stabilization) and a pH of 3.1. The balance on that wine is really nice now.

Acids above 9 in Riesling are pretty common, at least out here, and don't usually require any tinkering. Riesling ain't chard or pinot gris or gewurz and shouldn't be treated as if it were.

Dave

Tom,

I pretty sure I know the answer to this question but I'll ask it anyway. Have you ever ameliorated any wine with water??? Personally, I haven't but I know it's done in the northeast more than people might want to admit. I know it's an option to reducing acidity and he would have to add sugar to keep the brix level up but, do you or anyone else have any experience with that technique???

TIA,

Bob

Tom S wrote:

Dave,

The ph didn't change at all after fermentation and cold stablization??? Is that chemically possible??BTW, I like your last sentence.

Bob

Thanks to all of you for your input. As always, this newsgroup is a great help.

After listening to everything, I decided to use a little bit of bicarb to raise the pH a bit. Starting with a pH of 2.89 seemed awfully low. I did this, mainly, so that I wouldn't have to worry about that part later. So, the pH is now at about 3.1. In the meantime, I reserved a bit of the juice for a late mute, figuring that the residual sugar will cut the acidity.

I also added some sugar (horrors!!), as with an original brix of about

Sometimes, it's more rewarding for me to start with challenged grapes...at least then I have an excuse when things get screwed up. It's the perfect grapes that turn out bad that really bother me.

As an amateur, Dave's last comment really hit home. Too often people have an idea of what good wine should taste like, without recognizing that different grapes SHOULD have their own characteristics. This has been one of the hardest lessons for me to learn.

Thanks again,

Lee

Point taken, David, but he's not at 3.1 pH. He reported 2.89, which IMO will render the wine anywhere from unpleasant to undrinkable.

Tom S

I have never added water to my wines (except for that used to suspend or dissolve fining agents or sulfite), but the practice isn't uncommon here in California. I once heard a winemaker refer to the technique as "profit extending".

Usually water additions are done on severely overripe fruit in order to attain some semblance of balance in the finished wine and to assure that the fermentation will go to completion. In these cases tartaric additions are also necessary or the wine would end up very flat, because in overripe fruit the acid is quite low to start with. Typical numbers for such fruit might be 28° Brix at 4.0 pH and 0.4 TA, or worse.

Tom S

Hey Bob,

You're right--that is odd. Could be that the pH was higher right after fermentation, then dropped with cold stabilization. I don't normally worry about pH, so long as it's below 3.5

Dave

Yeah, I did wonder about that, and thought about asking whether the wine was at 65 or so when that pH was taken. Low temps will drop the pH right down there.

I also haven't found pH to have nearly as great an effect on taste as TA, but you're right that I'm never below 3.

Dave