Oak for spirits: what we know, and what we are still working on
Our staves, inserts and chips were designed for wine. Distillers ask for them more and more, so it is only fair to say plainly where our measurements stop.
Barrel ageing is a long tradition, expensive and variable from one vessel to the next. Alternative oak removes none of those three things, it shifts only one: variability. At the same dose and the same profile, two tanks oaked the same way resemble each other more than two barrels do. That is the starting point, and it is not enough on its own to make a good spirit.
Why extraction behaves differently than in wine
A spirit sits between 40 and 70 % vol. At that strength alcohol is a better solvent than wine for part of the wood compounds, and extraction is faster. That is what we see in our own trials, without being able today to give you a reliable coefficient that would hold for every spirit: an agricultural rum, an armagnac and a malt whisky do not respond in the same way.
The second difference is that microbial activity is very low in a spirit, which makes the process simpler to run than a tank of wine. It removes none of the hygiene precautions, it simply removes one source of accident.
What we do not yet know is the share of oxygen in the final result. In wine we measure it poorly as soon as the tank goes beyond a few hectoliters. In spirits we do not have enough hindsight to claim anything at all.
Which formats, and for how long?
The durations below are those of our technical sheets, established on wine. We give them as a starting point, not as a protocol for a spirit.
| Format | Thickness | Reference contact time (in wine) |
|---|---|---|
| Fine chips | 2 to 4 mm | 1 month minimum, 2 to 3 months to reach the plateau |
| Staves | 7 mm | 4 months minimum |
| Staves | 18 mm | 7 months minimum |
| Barrel inserts, in sticks | 22 mm | the length of a barrel ageing |
| EBX #410 liquid oak | density 1.080 kg/l at 20 °C, dry extract 180 g/l | 3 to 6 months for full integration |
Inserts follow the same physics in a cask as in a barrel of wine. The equivalence benchmarks we publish for wine, however, do not transfer to spirits: at 40 % vol. extraction does not follow the same rules, and we have no validated table for eaux-de-vie. The figures in grams and units per hectoliter are in our conversion table.
Which profile for which spirit?
Our two ranges read simply. Each Primary Color carries one character, to be blended by you: #13 Vanilla for roundness, #22 Toffee for caramel and crème brûlée, #24 Black Coffee for roasted coffee and cocoa, #14 Spicy for pepper and clove. La Recette, our pre-blended range, does not exist for spirits yet.
These descriptions come from our own tastings, carried out on wine and on model solution. The same profile does not land in the same place in a spirit at 55 % vol. We encourage you to trial on a small volume before committing a batch.
Does it replace the cask?
No, and we do not present it that way. What we see with our customers is rather a combination: a first oak contribution in tank to lay a base, then time in cask for the oxygen and the years. Some also use inserts to bring contribution back to casks that have already done several fills, without renewing the whole set. The oak we work with is air-dried for 36 months before toasting, which remains the same starting point as for a barrel.
How to try without losing a batch
On a test volume, at a low dose, and tasting at regular intervals rather than only at the end. A liquid oak is best assessed with a drop test, it is the quickest way to form an opinion: the protocol is here. Our tools propose figures, they do not decide. If a value looks wrong on your spirit, tell us: we would rather correct a figure than defend it.
Read next : Spirits and oak alternatives: what we see changing · Rancio is a journey