sour grapes

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berrycrush

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Just picked up my Chilean Pinot Noir today, oh boy it is green. I don't mean the color, actually there is no green berry anywhere in the clusters, even in the inside. I mean the numbers:
SG 1.086 ( Brix 20 )
PH 3.05
TA 5.6g/L
See photos:
https://www.flickr.com/photos/99052380@N06/albums/72157667724200816
I haven't made any wine from grapes so early picked. I am thinking let them sit on the stems for a week, maybe the number will improve? any thoughts?
 
The TA is rather low for that pH. If the grapes are already harvested, I don' know what waiting week would do for you other than let the grapes rot.
 
How much must do you have?
You could add back simple syrup with potassium tartrate/tartaric acid to raise your brix, TA, and your pH.
 
I later found out that the SG varies from lug to lug. Some lugs are as high as 22brix ( 1.10 SG). But PH is consistently low. My TA measurement has always been on the low side. Here is the problem, titration with grape juice is different from wine or other solutions because of the sugar(?) It gradually turns from pink to blue so it is hard to find the turning point. I read somewhere saying the sugar molecule caused this slow-turning. How do other members on the board overcome this?
 
I later found out that the SG varies from lug to lug. Some lugs are as high as 22brix ( 1.10 SG). But PH is consistently low. My TA measurement has always been on the low side. Here is the problem, titration with grape juice is different from wine or other solutions because of the sugar(?) It gradually turns from pink to blue so it is hard to find the turning point. I read somewhere saying the sugar molecule caused this slow-turning. How do other members on the board overcome this?

Use your pH meter to titrate, using an endpoint pH of 8.2.

Yes, the numbers will vary from cluster to cluster and grape to grape. And they can also change significantly in the hours post-crush. My process, FWIW, is to crush, and take measurements the next day, then adjust if necessary, then pitch yeast.

PS: I get SG of 1.092 at 22 brix, not 1.10 (http://www.brewersfriend.com/brix-converter/)
 
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