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Barrel-Aging Question

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Lee — Via Live Chat asks,
Q

My question regards micro-oxidation (and unfortunately, too much oxidation) in my small 8–10-gallon (30–38-L) barrels. I like the concentration of flavors that I get by aging my Bordeaux-style blends in my small barrels. I usually age in the barrels for 18–24 months. But lately, I’ve been getting too much of a nail polish smell, which I guess is acetaldehyde. Do you have any suggestions? I find that if I don’t age in barrels, my reds come out weak, without much body. I can’t use large barrels because of space considerations and weight. I try to top off regularly but I am sometimes lax. The main advantage of storing in the barrel for so long seems to be the concentration of flavors. My wines that have been evaporating and then topped off, seem to be “thicker,” which I like. Is there a way to get this effect, but with a shorter time in the barrel?

A
Unfortunately, with a small barrel like that, you’re going to have a high ratio of oxygen:wine. If you think about a traditional-sized barrel, it’s about 59 gallons (225 L); there’s a lot of wine in there. Especially if your barrel is much smaller, the surface area-to-wine ratio is much bigger for your mini-barrel than for a traditional barrel. Your 8–10 gallons (30–38 L) are therefore going to see a lot more wood contact, and a lot more oxygen transfer, than would 59 gallons (225 L) in a traditional, bigger barrel. This same principle is why some winemakers like to use bigger puncheons (like 132 gallons/500 L) so their wine gets proportionately less wood and oxygen exposure. This is popular in Rhône varieties like Grenache, Syrah, and Mourvèdre. I suggest you not use your barrel for as long as you’re talking about — you’re getting way too much oxygen there and as a result, like you say, too much acetaldehyde. First off, be sure you’ve got at least 25–30 ppm free SO2 in your wine to help keep the aldehydes down.
Response by Alison Crowe.