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!

A quick rule of thumb for pH adjustment. Say you want to shoot for pH
3.5. To calculate the amount of acid to subtract the desired pH, from
the starting pH, and the divide by 0.15. Hence (3.8-3.5)/0.15 = 0.3/0.15
= 2 g/L. This is how much I would have added then. Generally about half
of the acid would have dropped out straight away, and a bit more down
the track, but in your case this would not have happened.

Check the pH TA after malolactic. If the pH is greater than 3.65, then
cold stabilising will raise the pH. If it is less than 3.65 then the pH
will drop during cold stabilising. Hence upon completion of malo check
pH, TA, and adust pH down to say 3.5 or 3.4 if you have room without
blowing you TA too high. Remember that SO2 works much better at a pH 3.4
or 3.3 than at 3.6, and hence the wine will last much longer. Earlier
you add the acid, the less affect it has on the final TA. Be brave early
on and you will have a wine which lasts well.


James.




>
> 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
>