Friday, 12 June 2015

Cask beer in the 1950’s – the humble bung

Remember my insanely-detailed series of posts about cask beer in the 1950’s? Well I’m back with more, having found an insanely-detailed article about shives and spiles.

They’re pieces of equipment 100% specific to cask beer. The only even vaguely similar beer, Bayerischer Anstich, handles venting differently. Often they use a brass tap in the equivalent of the bung hole, turning it on when they need to let air into the cask.

By D. M. Edmonds
A shive, we are inclined I to assume, is just a bung. So it is; but it is also a piece of wood which remains in contact with the beer from racking till the time of tapping. Thin is quite long enough for an undesirable flavour to be imparted to the beer, or for a considerable amount of beer to be lost through leakage. The condition in which draught beer reaches the customer is very largely dependent on the choice and proper use of shives and hard (tight) and soft (porous) spiles.”
"Brewing Trade Review, 1950", page 117.

It’s a good point about the shive being in contact with the beer all the time it’s in the cask. That in itself limits the materials it can be made from. We learned earlier of the importance of the proper use of spiles.

Here’s something about the physical requirements of a shive:

“What then are the properties which a good shive mast have, and, which will determine the choice of timber for its manufacture? In the first place it must be soft, to avoid undue wear on bushes and bung-staves. It must, for obvious reasons, be tasteless, odourless and non-porous, and there must be no leakage through the side grain. In addition it should break "short," in order to allow of easy knocking away of the centre portion for spiling, but it should not be too brittle.”
"Brewing Trade Review, 1950", page 117.

See? It needs to be soft so you can bang it in without damaging other bits of the barrel and forms a good seal. Also you don’t want it adding any flavour to the beer.

And which wood makes the perfect shive?

“The material which most nearly fulfils all the above conditions is the heart- wood of the Appalachian poplar, known in the trade as canary-wood, or American bung-poplar. Unfortunately this has been unobtainable in this country in recent years, though a little is now being allocated for the use of the brewing trade. The best substitute for bung-poplar is Finnish birch, and this is the wood of which most good quality shives are being made here to-day. It is slightly harder and more brittle than canary-wood, but imparts no flavour to the beer, and is perfectly; satisfactory in all other ways.”
"Brewing Trade Review, 1950", page 117.

Unlike with barrels, an American wood was perfect. But obviously the war would have messed up the supply of that. And I can’t imagine wood from Finland was available in the war years, either. Especially as Finland was on the wrong side for much of it.

What about British wood? Was any of that suitable? Sort of.

“Home-grown hard-woods, such as sycamore or beech, are sometimes used. The former is satisfactory, though inclined to be knotty and slightly porous. It is, however, very difficult to obtain in sufficient quantities. Beech is too hard, and is subject, to "dote." This is a fungus, causing decay, which is recognisable by black and cream-coloured vein-like markings in the timber affected. It causes porousness, but is not otherwise a serious defect, as any harmful bacteria associated with it will be destroyed in the kilning process described below.”
"Brewing Trade Review, 1950", pages 117 - 118.

Sycamore was knotty, porous and there wasn’t enough of it. Far from perfect, then. Beech was likely to be infected and was so hard it would eventually damage your barrels. That sound even less suitable.

Next time we’ll look at how shives were made.

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