Help with red wine sour taste

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dan_b

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Hi All,

This is my third year making red wine from fresh grapes, and each year has had the same problem: After primary fermentation is mostly done and the sugar dissappears (SG < 1010), all I can taste is the wines acid. Firstly, my grapes this year were:

OG: 1098 (about 23 Brix)
PH: 3.2
TA: 6.5/7 ish

I know this is a little low on the PH , but it's hardy miles away from where it should be, and the wine is so sour/tart it's completely undrinkable. Also, last year's batch had a PH around 3.4 and that still had the same problem (i didn't have a TA kit to measure that last year).

It's a week old today, so yes it's too young etc etc, but the last two years batches have had the same issue and the only way I managed to resolve it was to dump a whole load of de-acidifier into the wine.

I'm pretty sure it's not VA since it doesn't get worse over time (in fact in the last two years it has subsided over the course of 6 - 12 months, just not enough).

I did add malolactic bacteria in both the last two years and that didn't resolve the problem, although i am not convinced that MLF actually took place - I used an old packet of dried bacteria and didn't properly re-hydrate it.

So I guess I have two questions:

1) Is it normal that at the end of primary fermentation and before MLF the acid in the wine makes it taste very tart? (Implying I need to perform MLF to correct it, and the chances are that in the last two years MLF didn't work.)

2) If not, what else?

Thanks in advance

Dan
 
Hi All,

This is my third year making red wine from fresh grapes, and each year has had the same problem:

What variety of grapes did you use and where were they from?
Did you use the same grapes/source for 3 years or were they different?
Your starting numbers don't look out of the ballpark to me.
You can do all kinds of adjustments to your must before fermentation and then use additives after fermentation.
If you haven't seen this, here's a good article about adjusting your must:
https://winemakermag.com/1013-creating-a-balanced-must

I used to use local grapes and try to make these kinds of adjustments, but ended up with variable results, partly because the grapes changed drastically from year to year, partly because I didn't know what I was doing and partly because my measuring equipment was inadequate.
So these days, I go out of my way to get quality grapes and don't add anything except the yeast and the wine comes out great.
Its still early in the wine season and there's plenty of time to get grapes.
 
This year:
80% Tempranillo and 20% garnacha both from Spain.
Last year:
50% Tempranillo (Spain) and 50% Syrah (Italy).
2 Years ago:
50% Tempranillo (Spain) and 50% Sangiovaise (Italy).

I don't import the grapes (I'm in the UK), but I think the guy that does has been using the same vineyard in Spain each year for the Tempranillo. The Italian grapes probably come from different vineyards though.

Last year I kept the Syrah and Tempranillo separately and the Tempranillo's acid was not a problem (it was to begin with, but it subsided), I blended the two to try and make the Syrah drinkable but it wasn't enough, so I added the de-acidifier.
 
You are fortunate that the pH is low enough to allow you to make acid adjustments to decrease the tartness to the level you desire. Malolactic will reduce the acid a little but it really depends on how much malic acid you have in there to begin with. Hard to know without a professional lab running that assay.

Your best bet is to add about 0.75g/L of potassium bicarbonate for each 1g/L of TA you want to reduce. Be sure the pH does not get about 3.65 or you may have trouble with high pH (oxidation/spoilage risk) after MLF. Run this in a bench trial to ensure you don't overshoot. I simply pull out a 1L sample and mix it in really well before re-measuring. In the end you probably want a TA of 5-5.5g/L.

PS - I'm assuming TA is measured grams of tartaric acid, rather than citric.
 
One other thing that helps with finished wine is cold stabilization, before bottling.

It's just like it sounds. Once the one is finished and clear, put the carboy/demijohn someplace cold. Excess tartaric acid will precipitate out as "wine diamonds", and then you can rack off of it and bottle as usual.

You can do that with your finished wine now, in the bottles. After a couple of months (or longer) in a cold place, you will likely have a ton of wine diamonds in there (tartaric acid crystals) but can decant the wine from the bottle. It should make a huge difference!
 
Thanks All,

I know I can "correct" this with de-acidifying additions and cold stabilisation, it's just that i'm surprised by how high the level of sourness is for what seem like fairly reasonable PH and TA (It really is far too sour to drink). Is that expected? Is it normal to be too sour to drink and have to de-acidify with these kind of numbers?
 
MLF bacteria needs to be fresh and stored in the freezer. It isn't like yeast, you can't just leave it lying around in a drawer. It is expensive but for red wine there really isn't any alternative. Also your wine needs to be at 18C or more, too cold and it won't happen.
 
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