Chemistry help

[rwallick11785]

I just got 220 lbs of Michigan Cabernet franc. I was pretty impressed to see it read 24 brix. When I ran pH it was 3.58 and the acidity was .51. I know the acid is low and since I plan to do malolactic I know it will drop further and the pH will rise. My question is this: can I run a pH test during regular alcoholic fermentation or will the yeast, etc. skew the reading? I ask because I know I need to add tartaric acid to lower PH and increase acidity to about .65 TA and hope the pH follows suit

 

[winemaker_3352]

I would adjust TA/PH before fermentation or after fermentation - not during.

IMO - those readings are not that bad - maybe a little low considering you are doing an MLF - i prefer my reds on the lower end of the TA scale - .55 - .60..

 

[rwallick11785]

Do u think they'll change a lot during alcoholic and ML fermentation?

 

[rwallick11785]

Any thoughts on how much tartaric acid to add? I have 29.5 gallons of must

 

[winemaker_3352]

Any thoughts on how much tartaric acid to add? I have 29.5 gallons of must

I am not sure how much it will affect the TA/PH from MLF.

How much acid you add depends on what you want your target TA/PH to be...

 

[ibglowin]

The CO2 can mess with the pH reading therefore its better to adjust before hand or afterwards. I think you need about 30gm total for that size and those numbers. I would add 15gms and stir well, let it sit for an hour then stir well again and take your pH and TA reading. Always add 1/2 what you think you need as you can always add more but its next to impossible to take it out once its in there.

 

[winemaker_3352]

Sorry rwallick11785 - i forgot in your first post you listed your numbers.

to get you TA from .51 to .65 for 29.5 gallons - adding 5.51 ounces should get you there.

But I would do like Mike said - I would add half of that - start with 3 ounces (3 tablespoons).

Re-measure - then adjust again - if you are relatively close to your target TA - I would advice adding a tsp at a time until you are there.

If you are still not close to your target TA - add a tablespoon at a time until you get close enough then start adding tsp at a time.

Keep track of how much a tsp or tblspn increases your TA - this can help figure out how much you need as well.

 

[rwallick11785]

I pitched the yeast to avoid issues with the lag time and oxidation or spontaneous fermentation. The must is still very cold so I'm hoping that by the time I can get the tartaric acid and add it that fermentation won't have started. Any thoughts about adding acid immediately after primary and before MLF? Just wondering since I will take your advice about adding 15 grams now and seeing where it comes out? I read somewhere that adding acid to whole must is the best but I also think that the wine will age long enough that adding it after pressing will still give the acid enough time to integrate into the overall profile of the wine. Any thoughts?

 

[rwallick11785]

With close to that 5.5 number too. I will try adding a little at a time. At this point I feel like if I get close I should be able to adjust later if needed. I just don't want to end up with something that is really unstable after everything is done and then end up with adding acid late in the process. Does that sound correct!

 

[john-c]

Food for thought - the TA number in my opinion is barely low; however the the pH number is low as well. As you bring up that TA you will see your pH drop resulting in correct acid but strenght that may show as tart or sour on the tongue. If you then do an ML secondary fermentation, the TA will change and based on where your pH is (below 3.8) it will fall as well and you may end up near or below the stability threshold of red wines (3.2pH). My guess you will end up with softer Lactic acids with strength requiring another adjustment post secondary to bring that pH up (K-carbo) so it doesnt bite and the wine remains stable (and the right color). Personally I would adjust the TA up to .62-.65 and see where your pH lands based on the buffering capacity of the wine. Based on that then gauge whether ML is really necessary (stylistically) or if you are better off just oaking and testing again in Spring to see where you ended up. You can always readjust then and give the wine 90 to marry before bottling in the event you had a spontaneous ML from the oak. I would certainly do a paper-chromo after the primary and again in Spring no matter your style wants with these numbers.