High-pH Wine

TroubleShooting

Hunter Nolen — New Braunfels, Texas asks,

Thanks again for your help in saving my high-sugar Viognier a couple of years ago. It is all gone now! I grow Syrah, Tempranillo, and Mourvèdre. In the Texas Hill Country the grapes “cry uncle” around the third week of July and I have to harvest or they will abruptly collapse in the relentless 100 °F (38 °C)+ heat. Because of the abruptness of collapse, I have learned to pick early rather than late because early means usable grapes and late means mush! I therefore end up picking on the third weekend in July when I can generally count on little rot, decent maturity, and available family and friends to help.

Also, due to the daytime heat and little relief through the night, I generally wind up with high pH. This year my pH came in at what I consider quite acidic for my vineyard (3.4), while my sugar was light (about 21 °Brix). I therefore chaptalized to about 24 °Brix before pitching my yeast. After fermentation, my pH had risen to right around 3.7, and I get a little nervous about long-term stability above 3.65. My inclination has always been to acidulate to around 3.65, which makes me more comfortable and usually does not tarten up the wine too terribly much.

I am generally inclined to conduct MLF on my red wine even though the pH is on the high side. I like to know my wine is stable for the long run, and generally favor the idea of converting my malic acid to lactic acid for flavor and mouthfeel reasons. But, I have seen some literature that suggests foregoing MLF on high-pH wines. This year I have done no acidulation yet and started my MLF culture going on the pH 3.7 wine. Finally, after MLF this year I fully expect my pH to be up around 3.8.

OK, enough of the chatter. My questions below in orange