American Oak (continued).
In last month's notes an account was given of the work carried out by the Institute of Brewing after the last war in connection with the use of American oak for beer casks in this country, and a brief summary of the conclusions then reached was included. This month a more difficult point is under discussion — viz., how to treat American oak so as to prevent, or minimise, the objectionable flavour which it notoriously tends to impart to British beers.
Opinions in the brewing industry vary enormously on the suitability or otherwise of American oak for British beers, some asserting that if properly treated it provides quite a suitable cask material, whilst others are equally vehement in its condemnation.
This divergence of opinion suggests that the extractiveness of different beers may vary, and that whereas one beer may suffer little from contact with this type of timber, others extract therefrom undesirable flavouring substances which give rise to "tainted" or "woody " complaints.
A more feasible hypothesis is, perhaps, that different types of "white oak" have been used in the different cases, or that the treatments employed have been different. A cask made from newly felled, unseasoned "white oak" of an unsuitable species is sure to give violently disagreeable flavours when it is filled with beer, no matter what preliminary treatment may have been employed to minimise this. We have had personal experience of casks of this type, and we can testify that even when lined, "pickled" and treated by every - known trick, they will continue to contaminate every lot of beer with which they are filled, until they are eventually broken down and thrown away. Even one stave of timber of this kind is enough to taint the whole contents of the cask.
Careful selection of timber by an experienced buyer is essential at the very start if any success is to be obtained with American oak casks. The timber must be carefully stacked and seasoned, and should not be used as long as there is any sign of wetness. Even with well-chosen, well-seasoned timber, lining is probably advisable, and even essential in many cases. The ideal lining from the flavour point of view is something completely insulating the beer from contact with the timber. Pitch probably fulfils this condition best, but few British breweries are equipped with the plant necessary for this process, so one of the proprietary enamels will probably be the best choice for lining purposes. These enamels, which consist of plastic material dissolved in a volatile organic solvent, act partly by penetrating the pores of the timber rather than as impervious linings, and there is no doubt that they minimise "taint" due to the use of American oak in a large number of casts. Miracles should not be expected, however, and every care should be taken in the original selection and treatment of the timber so that violent taint is avoided in the first place.
Heavy firing of the cask is another expedient which may be found successful in combating timber taint in some cases.
"The Brewers' Journal 1940" page 571. (Published July 17th, 1940.)
It's not so much the fact that some American oak made beer pong that interests me. Though, given that a single stave of the wrong oak was enough to bugger any beer put into the barrel, it was a pretty serious problem. No, it's not that. It's the suggested remedy. Lining.
I've been looking for hard evidence on the lining of wooden barrels in Britain for some time. It's frustratingly difficult to track down. But this article provides some vital clues.
For the wood to taint beer, they need to come into direct contact. So the implication of this article is that barrels weren't usually lined. If they were, you wouldn't need to worry about a funny taste from the oak. The assertion "few British breweries are equipped with the plant necessary for this process" about pitch-lining makes it clear that this practice wasn't common.
I now feel confident in saying that most British barrels were unlined until at least 1940. Good to know.