Is this MLF Finished or Not?

[jsbeckton]

St


Still check the TA, if nothing else, it’ll give you a reference point for future endeavors.

Checked again and no change, still 0.975 so looks like I’ll have to reduce the acid. A few questions:

1) is it normal for the acid to go from 0.675 to 0.975 during fermentation or must there have been something wrong with my initial measurement? I did measure multiple times before adding acid.
2) the acidex I have says that the wine must be fined first. Was hoping not to fine but does this mean I have no choice?
3) both my acid test kit and the acidex that I have say that the wine should be CS after addition but it was noted above that for a low pH CS will actually increase acidity. What should I do?
4) is there a TA that I should go for or do I need to do 3 samples targeting a reduction of 0.1, 0.2 and 0.3 and see which seems best?
5) anything else I should be considering?

Thanks!

 

[Johnd]

Checked again and no change, still 0.975 so looks like I’ll have to reduce the acid. A few questions:

1) is it normal for the acid to go from 0.675 to 0.975 during fermentation or must there have been something wrong with my initial measurement? I did measure multiple times before adding acid.
2) the acidex I have says that the wine must be fined first. Was hoping not to fine but does this mean I have no choice?
3) both my acid test kit and the acidex that I have say that the wine should be CS after addition but it was noted above that for a low pH CS will actually increase acidity. What should I do?
4) is there a TA that I should go for or do I need to do 3 samples targeting a reduction of 0.1, 0.2 and 0.3 and see which seems best?
5) anything else I should be considering?

Thanks!

1. No, something else was off. Initial readings, must not blended and strained, something was off causing you to add acid.
2. Never used acidex, so cant say. I use K bicarbonate it bench trials to get to my best taste, reproduce on the batch sized scale, then store wine in the cellar at 55 for many months before bottling. Anything that’s going to precipitate out at 55 does so, and no more comes out in the bottle.
3. See # 2. The increase will be in pH, acid strength, but not in quantity of acid (TA). Acid reduction in an acidic wine is delicate, then there’s all of the head kicking for adding acid. Go slow, take weeks if you want, be methodical and plodding, you’ll make improvements.
4. Bench trials for best taste

 

[jsbeckton]

Well...good thing is went with bench trials!

Was going for 0.1, 0.2 and 0.3 reductions of TA. Added about 5 days ago and have stores at 55F.

Results of degassed samples:

0.1 test: actually dropped TA by 0.30 and raised pH to 3.6. Tasted OK.

0.2 test: actually dropped TA by 0.44 and raised pH to 4.1. Tastes bad.

0.3 test: actually dropped TA by 0.51 and raised pH to 4.6. This one was undrinkable.

My k-bicarbonate says 1-1/3 tsp/gal rather than by weight so I weighed this volume and then used that to get weight which I scaled down. I checked my math again ad came up with same additions so not sure why it’s so far off.

Thinking that I am going to do 3 new bench trials using 1/3, 2/3 and 3/3 of the amount that was supposed to give me the reduction of 0.1 for these trials.

I was also going to CS this sample just to see what difference it makes on pH.

Any thoughts on this?

 

[stickman]

Don't use any conversions from volume like tsp, that's just a rough guide for those that don't have a scale. For the trial, weigh the potassium bicarbonate directly, use 0.673 g/L to remove approximately 1 g/L tartaric. If your final pH happens to be around 3.6, then it probably wont change much during CS, but pH at this point is not the main concern, main concern is taste. CS will cause an additional 25% to 50% of acid reduction depending on pH as well as other factors, so use less potassium bicarbonate for the main batch than what is determined during the trial. As @Johnd said, go slow, you can always add more if needed.

 

[jsbeckton]

Don't use any conversions from volume like tsp, that's just a rough guide for those that don't have a scale. For the trial, weigh the potassium bicarbonate directly, use 0.673 g/L to remove approximately 1 g/L tartaric. If your final pH happens to be around 3.6, then it probably wont change much during CS, but pH at this point is not the main concern, main concern is taste. CS will cause an additional 25% to 50% of acid reduction depending on pH as well as other factors, so use less potassium bicarbonate for the main batch than what is determined during the trial. As @Johnd said, go slow, you can always add more if needed.

Yeah, I really didn’t like doing the conversion but the product that I had didn’t have any other dosing info. I was wondering if all k-bicarbonate was the same so I could use more accurate weight measurements that I found online but can try as you suggested above.

I did note that Midwest supplies states that you are supposed to use 1g/L for a 0.1 reduction so maybe every brand is a bit different?

 

[Johnd]

I did note that Midwest supplies states that you are supposed to use 1g/L for a 0.1 reduction so maybe every brand is a bit different?

There may be brands with different concentrations, but the ones that I've used have all performed in the range of what @stickman indicated, doing way more than anticipated, and you just never know how a wine / must will react, as they are ALL different. The slow, methodical, plodding adjustments of acid are for just that reason, you can always add more, but it's super hard to take it back............

 

[jsbeckton]

Ok, so I did bench trials and then added K-bicarbonate. Bench trials suggested it would come out to TA of .67 and a pH of 3.4. It was close at a TA of .71 and a pH of 3.3. Tastes pretty good but a touch tart and looks pinkish purple due to the low pH. Would you guys tweak it again to try and bump the pH up to 3.4 or leave it alone?

 

[Boatboy24]

I'd leave it. You're bound to end up at 3.5 and be asking yourself the same question again.