2013 Marquette

[GreginND]

I am purchasing some Marquette grapes from a local grower this year. The numbers over the last month have been very consistently rising:

Date pH Brix
29-Aug 2.6 20.8
5-Sep 2.71 23
12-Sep 2.81 23.6
19-Sep 2.92 25

Of course they are anxious to pick as soon as possible. I'm telling them to give it at a minimum another week - even better two weeks. I'd like to have the pH closer to 3.2. So far it has been a consistent drop in acid of ~0.1 pH every week. At this rate it will take 3 more weeks.

Those more knowledgable - would you think the acid will drop faster as it gets closer? Any insight on how much more time these need?

Thanks.

 

[grapeman]

Greg check the TA also. University of Minnesota lists the average for years 2003-2005 as brix 25.7, pH 2.9 and TA as 12.3 g/L. Last year the pH got up to about 3.2 which is the highest I have ever seen it and the TA dropped to 12.2. You are in the normal range now so try to wait as long as you can, but don't wait beyond when your supplier is comfortable as they can develop botrytis quickly when they get very ripe.

 

[GreginND]

Thanks for the info. We've seen a bit better numbers around here the last couple years. The vineyard down the road in Absaraka had pH 3.05 on Sep 5!

My grower is going to let them hang until Sep 28. I'll warn them to watch for botrytis. They don't have the setup to measure TA (I know, I know). I could do it but they are far enough away that it is inconvenient. I think if the pH can get above 3 the TA's should be in a good range.