One thought I have is that those cool-ripening grapes may have had
mostly malic acid and very little tartaric acid. I've seen that before
in grapes from cool climates.
When you do ML fermentation on such grapes, once the malic is converted
to lactic acid, there is little to no total acidity left.
Next year you may want to measure the malic acid content as well as the
total acidity to assess if this is what really happened to you.
If it is, you probably will want to add tartaric acid to the must.

Hope this helps.
Gene

Darin wrote:
> Hello all -
>
> I made a barrel of Chardonnay this year from fresh fruit, and I
> thought I'd appeal to the group to help me understand and solve a
> couple of issues that have arisen.
>
> I started with a ½ ton of BC Okanagan Chardonnay grapes, night picked,
> when sugar content had reached 23 Brix and my farmer thought the
> grapes had sufficient maturity. After crushing the following morning,
> I measured 7.10g/L TA with pH 3.37.
>
> I cold fermented at about 55 degrees F, warmed and ran ML (ah, and the
> enjoyable butter it did produce!), and upon completion added S02 and
> cold stabilised in my garage (near freezing) till the end of
> December. However, when tasting the wine for the first time since
> chilled, I found it flat with a degassed pH of 3.80. Yikes!
>
> I added 0.90 g/l tartaric acid (after trials) and schlepped my tanks
> back into the pseudo-cold of a BC coastal winter. Before bentonite
> fining at the end of March, I noted that more tartrate salts had
> precipitated in the tanks, it still tasted slightly flat, pH was 3.58,
> and TA was skulking around 5.70g/L. I popped in another 0.30 g/L
> tartaric and let it sit in my cellar (55 degrees) until last week.
>
> My current sample weighs in at pH 3.55 and may yet be a bit flat. I
> was worried about more precipitation from my earlier 0.30 addition, so
> I chilled a sample in the fridge for the last week - nary a single
> crystal, though.
>
> I wonder:
>
> 1. Why won't this wine precipitate any further tartrate when I added
> 0.30g/L after cold stabilisation? Is it stable?
>
> 2. If I add another 0.20 g/L, filter with 50micron nominal pads, and
> then bottle, am I going to be seeing white crystals in my future?
>
> 3. How can I mitigate this problem next year? I've been considering
> front-loading tartaric acid before ferment (even though my must will
> likely originate around pH3.37 with TA 7.1) or even halting ML
> midstream by means of early S02 addition.
>
> I'm trying to get my ducks straight this year, but I'm also leading a
> club next year, so any advice would most appreciatively be
> appreciated.
>
> Best Regards & In Vino Veritas
> Darin
>