Just harvested Pinot Noir- 4.9 TA AND 3.3pH???

[gates]

Hi-

I'm really scratching my head- we just finished harvesting a couple tons of pinot noir from Eola-Amity in Oregon. I took a sample to ETS labs for an initial juice panel and got the following:

pH: 3.31
TA: 4.9 g/L
L-malic: 1.22 g/L
brix: 23.2
YAN: 95 mg/L
potassium: 1270 mg/L

My first reaction was to mistrust the lab's results: how could the pH be so low with such a low TA? However, I performed a subsequent titration for TA myself, with a must sample blended in a high-speed blender first, and got the same results.

Could the high potassium be somehow binding with tartaric acid in the must and therefore keeping it from showing up in the titration? Or are there other acids present that would be lowering the pH? The initial thought would be malic, but at only 1.22 g/L it seems too low to have the necessary downward influence on pH.

The big question is: what to do? Should we correct with tartaric acid to bring TA up to the 6-7 range, disregarding the impact on pH, or wait and taste it, and risk a barrel addition that might be noticeable in the glass?

We plan on doing MLF (pH up), and could possibly do a cold stabilization to try and drop some of the potassium out (pH down). The problem with dropping the tartrates obviously is that our TA will be even lower.

No one I've talked to knows what's going on here- does anyone have any ideas?

Thanks a lot for taking the time!

 

[ibglowin]

I wouldn't add any acid with that pH and would be inclined to let it roll and see where it ends up at post MLF.

 

[oregondabbler]

(I live about 30 miles south of Eola/Amity) We had a good rain about 3 weeks ago followed by warm, dry weather. I'm just guessing but, here goes: Low acid indicates the fruit was well into the stages of ripening. The high potassium and low pH are maybe due to less water than expected in the fruit?

How did the fruit look? I'm wondering if you saw much raisining. I saw some raisining in my PN grapes when I harvested on Sunday (10/12). I haven't tested for pH or TA yet -- I'll test when I pitch yeast tomorrow or the day after -- but I might see something like you did. I'll let you know if I do.

Anyway, this is all speculation. For what to do, what Mike says.

let it roll and see where it ends up at post MLF.

 

[gates]

Our grapes actually looked great. Not much dehydration at all.

 

[HillPeople]

This may help:
http://morewinemaking.com/articles/complete_must_adjustment_pH_TA_Brix

Or this:
http://www.bcawa.ca/winemaking/acidph.htm

I suspect the potassium is buffering the TA.

 

[oregondabbler]

I'm just guessing but, here goes: Low acid indicates the fruit was well into the stages of ripening. The high potassium and low pH are maybe due to less water than expected in the fruit?

My silly wild *** guess was just that. I think I'll leave the speculating to people that know more.

My own grapes came in a little low in brix (20%-23% depending on variety) and a little high in acid. As normal.