Ask Wine Wizard

Alternative Sweeteners

TroubleShooting

Daniel Page — Council, Idaho asks,
Q

I grow and make Cabernet Sauvignon and Merlot in southwest Idaho. The season is intense but short. In order to reach decent ripeness (~25 °Brix), I have been growing with a very high leaf-to-cluster ratio. The wine is fairly good but has high pH values. I adjust the must with tartaric acid to an acceptable value (~3.7), but malolactic fermentation always drives it over 4.0. I’m not sure what causes the high pH — soil composition, leaf ratio, or a combination of both. To bring down the pH I have to add so much acid it unbalances the wine. If I add a little sweetener it does make it quite drinkable. Can I use Splenda or stevia at bottling or will that breakdown and ferment like sugar? Your thoughts will be greatly appreciated.

A
I hear you on the high pH/high TA unbalanced wine issue. I myself have dealt with some vineyards and some wine lots where I have had to add so much tartaric to high pH musts just to keep the pH below 3.85 after malolactic is complete. The causes of this in the vineyard is worth its own article or articles as the sources are as complex as the methods for dealing with the resulting wines. High potassium in the musts can be a cause, (which needs to be addressed in the vineyard). Over cropping and a dense canopy can sometimes cause a high malate/high tartaric situation so that when the wine goes through malolactic fermentation (MLF), the resulting wine is unbalanced and in what I would certainly call a “microbial spoilage danger zone” with a pH higher than 3.80. At some point, all you can do is keep adding the tartaric to bring that pH down. As you’ve found out, however, you risk getting some sharp off-flavors; also as you’ve found out, a little sweetness can really help mask or
Response by Alison Crowe.