Lining casks with pitch

Pitch. And the age-old question: were British beer casks lined with pitch? Some swear blind that they were. What do I think? I'll tell you in a minute. After we've looked at some old texts.

First, one from the early in the 19th century. It's part of a discussion on the methods employed in German brewing:

"Great care is requisite in having the store-casks very clean and sweet before filling them, lest they should communicate a disagreeable flavour to the beer. In two towns, this is effected, after they are well washed, by smoking them with burning sulphur; but in the rest of Bavaria it is done by lining them with pitch. The following is the manner by which this is effected at Munich. The store-casks, in which the beer is cleansed, are previously pitched every time for summer beer, and once a year for winter beer. Pitching is practised in this way:—One end of the cask is taken out, and two English pounds of pitch for every barrel of its contents, if the pitching has only to be renewed (but double that quantity if for the first time), is set fire to on the bottom of the cask, and made to burn until the whole has become perfectly fluid. This being done, the fire is extinguished, by putting in the, head of the cask and driving the hoops close ; and then the cask is rolled about and turned in every direction, so that the pitch may be spread over every part of the inner surface, which it will thereby cover with a crust of one-eighth of an inch thick. This crust is apt to crack and blister, which causes the necessity of re-pitching every season. The professed object of this manipulation is cleanliness; but it doubtless communicates a peculiar flavour to the beer, which, however, is liked, and consequently required, by the customers of those brewers."
"The Art of Brewing" by David Booth, 1834, page 29.

Nothing directly about pitching barrels in British breweries, but the implication is that this is a pratice not known in Britain. There's no mention of "this is how we do pitching in Britain". And the impact of pitch on beer flavour is remarked upon. Not the most convincing piece of evidence, I will admit.

Let's look at another text from a couple of decades later:

"The German brewers, who have the repute of being far our superiors, have doubtlessly seen the inconvenience arising from the casks absorbing the beer, and inflicting injury by admitting the atmospheric air through their pores, both casks and contents suffering upon the decomposition of the imbibed fluids, and the consequent acidity of the wood. Hence their precaution of lining their casks with pitch. No such protection is taken by other brewers; but notwithstanding that such or any similar "new-fangled notion" may be jeered at by the anti-innovators of the British brewery, the subject assuredly deserves a little thought; and the author suggests that brewers' casks may be rendered more durable, and their pores may be effectually stopped, by subjecting all casks, whether old or new, to the following process."
"The theory and practice of brewing illustrated", by William Tizard, 1850, page 489.

This is much clearer. The Germans, clever devils that they are, did pitch their barrels. Britain's brewers, being a conservative bunch, didn't. I think this is very clear evidence against pitching in Britain.



Now a text from the early 20th century:

"The wooden casks used for the transport and storage of wine, beer, etc., are liable to become infested with mould fungi and other bacteria when lying empty, and must therefore be carefully cleansed, before use again, with boiling water and some disinfectant, such as lime, etc., and then dried. Even then, no security exists against the contamination of the liquid contents, or at any rate against their acquiring a flavour due to the cask. In the case of beer barrels, it has long been the practice (in some parts of the Continent) to line them with pitch, which, however, is liable to crack and peel off, so that not only is the beer contaminated with fragments of pitch, but the cracks in the coating afford an excellent harbouring place for the development of bacteria. It is true that shellac dissolved in spirit has also been used for varnishing the interior of these casks ; but that process in turn has drawbacks which preclude its employment in many cases."
"Casein, its preparation and technical utilisation" by Robert Scherer, 1911, pages 149-150.

That's pretty clear: pitching is something performed in parts of the Continent. So not in Britain.

To round off today's post, two fairly random passages about pitching barrels:

"Turbidity of beer due to resins is a very rare occurrence ; it is generally attributed to the separation of resins extracted from the hops. The author, however, cannot admit that hop resins are present in the beer in such quantities as to cause a visible turbidity. The small quantity which fails to settle out with the yeast is found in the sediments from the lager casks. The author has recently examined a number of samples of beer, more or less turbid, and possessing a distinct flavour of pitch. The microscopic examination of these turbid samples showed that the turbidity was caused solely by the presence of globules of resin. On applying pressure to the cover-glass it was found that these globules varied in consistency, as if the resin were dissolved in some solvent in varying proportions. The globules were separated by centrifugalising some of the beer; they were then placed on to gypsum plate to remove most of the water, and moistened with a reagent composed of a mixture of 5 c.c. of acetic anhydride and one or two drops of concentrated sulphuric acid. A violet coloration was thus developed—a conclusive proof that tho turbidity was caused, not by hop resins, but by rosin derived from the pitch lining of the casks. It is not yet clear how this pitch is absorbed by the beer, but it is very probably due to overheating when coating the casks, and the consequent formation of rosin oil, which appears as a bluish iridescent layer over the surface of the pitch after cooling. The microscopic appearance of the cuntrifugalised centrifugalised rosin particles may vary from characteristic globules, through intermediate forms, to roundish, indefinitely shaped particles, which tend to adhere in masses, and have a shrunken, honeycombed appearance, ranging from colourless to yellowish-brown."
"Journal of the Society of Chemical Industry, Volume 23", 1904, page 126.

So there were problems associated with lining barrels. I'm not sure I'd be happy if I found lumps of pitch in my pint.

And finally a positively scary property of lined barrels:

"A Cause of Explosions in Lining Casks with Pitch. By J. Brand (Zeits. ges. Brauw., 1901, 24, 481—483).

Several explosions have been recently recorded in the course of lining casks with pitch by means of the Theurer apparatus, some of which cases could not be due to the vapours lighting back from a fire since they were not conducted into a fire at all. In considering the question, the author recalled to mind the explosions produced by statical electricity generated by friction in the benzine (petroleum spirit) " dry cleaning " process ; and, in view of the probability of a similar generation of electricity through the friction of the hot pitch sprayed into the casks, conducted several experiments with a small Theurer apparatus and a number of 6-12 gallon casks. These casks were pitched, and then tested as quickly as possible by inserting through the bunghole, to the depth of about a foot, a very sensitive electroscope with aluminium leaves. In the case of casks which had come direct to the pitching apparatus, from being steamed out and therefore contained water vapour, only two out of ten gave any positive results ; but when dry casks were tried a decided movement of the electroscope leaves was noticed in six out of ten, the divergence of the leaves in some instances being found to correspond to a tension of 300 volts, capable of producing a 0.1 mm. spark. Whether the risk of similar explosions could be diminished by the introduction of water vapour into the casks the author leaves an open question, but, at any rate, he considers that pitch containing the minimum amount of turpentine and similar volatile constituents is safer to use than such samples as give off a large quantity of volatile matter at the temperature of the pitching operation (about 200° C.)."
"Journal of the Institute of Brewing, Volume 7", 1901, pages 516 - 517.

What do I think? Did British breweries pitch line their casks? No. At least not before WW I.