Funny you mention this topic because I’m currently working on a lower-alcohol project at work (at Plata Wine Partners, I often develop custom projects for clients, and this is one). The brief for me is to come up with a delicious, balanced Pinot Noir and rosé that clock in around 9% alcohol. There is some evidence that the typical U.S. consumer is increasingly interested in buying and enjoying wines with more moderate levels of alcohol.
Like you, they seem to be interested in a) avoiding getting a little too tipsy and/or b) achieving health and wellness goals of reducing alcohol consumption like curtailing inflammation or lowering calorie consumption. Now, of course, for my project I’m going to have to use reverse osmosis machinery to physically remove some of the alcohol, something that your usual home winemaker won’t be dealing with. The process can cost thousands of dollars to employ and only larger-scale bottling runs can justify it. That being said there are many things that winemakers can employ to try to get balanced, delicious wines with naturally lower alcohol levels.
Whatever a winemaker’s goal, we all have to think about how alcohol plays (or doesn’t play) well with the other components in any given wine. Alcohol never stands alone and, contrary to what some wine advocacy groups would have us believe, isn’t the only component important for “balance.” Total acidity, pH, aromatic complexity, tannin, sugar, and carbon dioxide levels, especially, are all important pieces of the overall picture of a wine.
Bruce W. Zoecklein at Virginia Tech sketches out the below schematic, which explains the interactions:
Alcohol brings a sense of body to wine and can also increase the perception of tannin. Sugar can mask both acidity and tannin and also can give the impression of body and a “full” mouthfeel. It often is present in lower-alcohol wine because of these effects. In order to not have a product be too sweet, higher acid is often required to balance the sugar if present. Acid and phenolics reinforce and amplify each other so too much of one can bring out a negative in another. The most important thing to remember is that if alcohol is going to be lower, other “sweet” components have to be higher or something on the other side of the equation (acid + phenolics) has to be lower.
Carbon dioxide bubbles will contribute body, which is one of the reasons many sparkling wines can be so successful at lower alcohol levels. Floral, distinctive, or especially rich aromatic varietals as well, will help the “nose” take the place of some of the complexity that ripeness and alcohol might have contributed. For this reason, Chardonnay is hard to do on a low-alcohol level whereas Riesling can really shine.
Like I mention above, most winemakers aiming for lower-alcohol wines aren’t simply removing alcohol post-fermentation but are taking a systemic, holistic approach. Below are some techniques to employ if you are seeking to reduce the sugar levels in your grapes or the eventual alcohol levels in your wines.
Planning What to Make
- Plan to make varietals that don’t rely on the heft of booze for style and that bring other charms to the party. Floral and aromatic varietals like Riesling and Malvasia Bianca, for example, are lovely at lower alcohol levels. In your case, your Sauvignon Blanc may be a really great play. Instead of trying to make your Cabernet super “lite” maybe buy some Pinot Noir from a neighbor?
- Choose to make wine styles that naturally lend themselves to lower alcohol like low tannin, sparkling (or slightly spritzy . . . think vinho verde) products.
In the Vineyard
- Choose naturally lower-acid sites, especially those with hot nights (over 70 °F/21 °C) and lower diurnal fluctuation, which will burn off residual acid earlier in the season. Especially in whites, this will allow for full-flavored picking at lower Brix. I would think your Mendocino Sauvignon Blanc would be ideal for this.
- Hold off on irrigation as much as possible post-veraison. This pushes the vine into senescence and developing tannins earlier in the season.
- Don’t thin fruit too much. A higher tonnage per acre (contrary to popular belief) will assist to ripen fruit faster for a given leaf load.
- Remove laterals.
- Make sure you don’t have too much canopy, especially for reds. Dappled, open sunlight into the fruit zone is critical as it decreases malic acid during ripening. Also, you do not want bell pepper pyrazines in your Cabernet, so be especially careful here.
- Leaf pluck in the fruit zone, as long as a heat wave doesn’t threaten sunburn.
- Try box-pruning or “California sprawl” to get dappled sunlight into all of the vine.
- Get out in the vineyard and taste constantly as harvest approaches. Don’t be afraid to pick some “early lots” if you can in order to get some lower alcohol blenders. You may be surprised at the quality, especially if you’ve followed some of the above suggestions.
On the Crush Pad
- Add water generously to combat any berry dehydration. Water added early always integrates better.
- Adding untoasted oak dust/shavings at the crusher can help combat green flavors in red grapes.
In the Fermentation Vat
- Warmer fermentations (more suitable for reds than whites) can help “blow off” a certain amount of alcohol, perhaps 0.25–1%.
- Open top fermenters, like those often employed in producing Pinot Noir, can also contribute to ethanol “blow off” and reduce alcohol slightly by another 0.25–1%.
- For white wines that will not be 100% malic acid complete, choose a malic acid reducing yeast like Lalvin C. It gives a 30% reduction in malic acid during primary fermentation and “rounder” flavor without any undesired malolactic fermentation byproducts that may not be style appropriate.
- Try arresting fermentation, especially for whites that have higher acid, to leave a little residual sugar. This will result in a lower final alcohol and will balance out the higher acid/lower alcohol and lend some body to the finished wine that alcohol would’ve contributed.
In the Cellar
- Try blending lots from early-pick, warmer-night sites (see above, less acid) with those that come from higher-flavored, more “traditional” sites.
- Surprisingly, some of the newer tannin preparations from companies like Laffort, AEB, and Enartis can really smooth out rough phenolics and make “green” disappear in young and finished wines. I hear good things about the “Rouge” tannin from AEB and the “Dark Chocolate” tannin from Enartis. By removing green or rough-feeling tannins, the reduction of body-enhancing alcohol won’t be missed quite so much.
- If you are storing sweet wine, chill and/or filter in order to keep tabs on possible re-fermentation. Certainly sterile-filter the wine via crossflow or 0.45 micron nominal pad or cartridge if this is the case.
- I know you mentioned health as a goal, but don’t be afraid of adding 1–2 g/L residual sugar to achieve mouthfeel and flavor balance at bottling. I like to buy a little grape juice concentrate and meter it in maybe around 1–3 mL/L, just to give some roundness and add to the finish. Lower alcohol wines often need to be balanced in this way (sterile filter afterwards) and it can really help.