Sunday, October 10, 2010

2010 Zinfandel

I went to the local grape market, and found some wonderful "old vine" zinfandel grapes. I have taken to wondering around the warehouse looking for grapes that seem good to me. I originally was looking for Merlot grapes, and there were some good ones, but these zinfandel grapes were so more flavorful and sweet.

2010 Zinfandel Recipe

144 lb or 4 cases of "old vine" Zinfandel grapes from F. Colavita's of Stockton CA; crushed to juice;

13 g of ammonium bisulfite
10 g pectic enzyme

Let stand until morning.

10 g yeast energizer
900 ml water
2 packets of yeast - Montrachet

I crushed the grapes in my humble wood crank grape crusher. I pulled out the larger stems, but these grapes had a good number of sugary raisins so I left those stems in. I pulled a lot of stems out though, and I double crushed them by running them through the crusher twice.

Ammonium bisulfite is to kill the wild yeast. The pectic enzyme helps the wine to be clearer.

The density of the juice was 1.122g/ml, and the Brix   refractive index was 27.4. This should give a high alcohol content in the range of 16.7%. These grapes had a large number of raisins so I think the sugar content will probably go up. I added 900 ml of water, which should drop the alcohol to about 14%.

I decided to use two packets of yeast since the cabernet sauvignon fermentation was too slow.
My art photo using the zinfandel grapes. 


I tracked the refractive index over the first week.

Oct 10  7 PM       26.4 Brix  (Yeast added)
Oct  11 7 AM      26.4 Brix  (Its the same!!  :-(
Oct 11  8 PM        24.5
Oct 12  7 AM       19.2
Oct 13   no measurement, but huge volumes of carbon dioxide bubbles I spent time dividing the juice into two containers to avoid overflow
Oct 14  7 AM       9.5  (huge drop in Brix)
Oct 14  7 PM       9.5  (Its the same.)
Oct 15   7 AM      9.5  (Its the same?)
Oct 15  10 AM     9.5  (Strangely the same. Yes it measures water correctly.  The juice seems fermented by flavor.)

I pressed the grapes, which went well. I got 41 liters of juice from the four cases of grapes. 

Saturday, October 9, 2010

Muscato and Cabaret Sauvignon Update

As described below, I made the grape juice from the Muscato grapes, and fermented it for 7 days in open top primary fermentor before transferring to a demijohn. I got about 18 liters yield from the three cases of grapes. I did not adjust the sugar content.

I tracked the refractive index to monitor the fermentation:

27 Sept   23 (so called Brix units)
28 Sept   15
29 Sept    12
30 Sept     9
1  Oct       8

The book says that the refractive index should go negative before moving to a secondary fermentor, but I did not to that.

It has been a week since then, and the wine is slowly clarifying. The wine is not evolving carbon dioxide quickly though the trap though, so I am a little worried.


The cabaret sauvignon fermentation started more slowly. I monitored the refractive index twice a day since I was worried about it.

27 Sept   pm      24.4 (so called Brix units)
28 Sept  am       24.1
               pm      22.8  
29 Sept  am       21.8
               pm      19.7
30 Sept  am       15.8
              pm       13 
1  Oct    am       11.6
              pm      10.3
2 Oct     am        9.7

Similarly I wish I could have let this go farther. I pressed the grapes, and got about 36 L from the four cases of grapes.