What Could Lead To A Stalled MLF
TroubleShooting
Steven Mickelson — Chelan, Washington asks,
I have a small vineyard in the Chelan AVA (Washington state) and grow Merlot, Syrah, Malbec, Cabernet Sauvignon, and Cabernet Franc. This harvest season was late and ended prematurely (before full ripening) due to a hard freeze. The grapes other than the Merlot were only borderline ripe. Fermentation progressed nicely in all varieties, but only the Merlot successfully underwent MLF (malolactic fermentation). MLF in the others will not start despite re-inoculation attempts with three different commercial MLF strains (Wyeast 4007, Viniflora CH16, and Enoferm Alpha). Alcohol and pH are between 12.5–13.2% and 3.4–3.6, respectively, in the Syrah, Malbec, and Cabs. This has never been an issue in the past. Help!