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In reply to: 2022 Merlot
In reply to: 2022 Merlot
In reply to: 2022 Viognier
In reply to: Chemistry Results for 2020 Zin
In reply to: YAN and chemistry- Pinot Noir 2018
In reply to: YAN and chemistry- Pinot Noir 2018
In reply to: YAN and chemistry- Petite Verdot
In reply to: Chemistry
In reply to: Chemistry and YAN Posts – 2017 Pinot Noir
It’s interesting that the TA is so low. “Winery Technology & Operations by Yair Margolit mentions “The main reason for acid deficiency in must is the reduction of malic acid during the ripening period. ” see page 51 in the revised edition. He suggests adding Malic acid as one solution to this problem rather than tartaric. When using DL-malic acid only the L-malic isomer is consumed during the ML fermentation and the D-malic isomer is left and will not drop out during cold stabilization. He indicates this is a good way to re-establish the natural balance between the malic and tartaric acids in the grapes. So, if anyone has malic acid this sounds like a good alternative.
I will use tartaric since I don’t have malic and will use the average of Dave’s and Ian’s TA values to adjust my TA. Adding approximately 2.4g/L to bring the TA to 6.2 should bring my pH down to about 3.6 – 3.7. Since I don’t yet have a reliable NaOH solution I will just go with this. I would like to hear any comments on this strategy.
In reply to: Chemistry and YAN Posts – 2017 Pinot Noir
Hi all,
H2S problems should be rare. I have experienced them occasionally when I leave my new wine on the gros lees for too long. It is very important to check the wine at least twice a day for H2S. At this stage, it is easy to remove the problem by racking and splashing. O2 will rid you of the problem in most cases. If not, then a stir with a copper pipe helps. If you allow the disuphides to form then it’s a whole different problem.
I have noticed that many club members use a lot of sulphite on their crushed grapes. This too can lead to H2S problems. Use only the minimum amount. In my experience, it is rare that the grapes we receive require much sulphite at all and sometimes they have residual sulfur left over from from dusting. I often use none unless I intend to cold soak for more than two days. I have seldom had any problems.
Causes of H2S also include such things as poor sanitation and lack of proper nutrients. If you use Go Ferm or equivalent to start the yeast then you should have enough nutrients to start the fermentation until it is at least 1/3 complete. At which time, you should be adding additional nutrients such as Fermaid K and DAP.
Generally I assume a YAN of 150 without any lab results but I agree with Dave. And, adding too many nutrients can be as bad as not adding enough. Especially if you add them late in the fermentation.
Good luck,
Mickey Bliss
These are my experiences after 20 years of making good quality wine.
In reply to: Chemistry and Balancing
Chemistry Measurements: pH=3.86, TA avg = 6.0g/L, SpG = 26B
Notes: The pH is a little high and the TA a little low – will add 1g/L Tartaric Acid.
Will adjust Brix to 24 for 600lbs (150L) – add 88g Tartaric Acid and 12.5L water.*
*ref. Winery Technology & Operations, Dr. Yair Margalit, Wine Appreciation Guild, San Francisco, 1996In reply to: Viognier – Chemistry and Balancing
