Saturday, 17 April 2010

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.


Ed said...

Seeing as wooden casks haven't fully died out in Britain couldn't you just ask the guy from Wadsworths?

Ron Pattinson said...

Ed, they could tell mewaht they do today. But that wouldn't answer my question about what happened pre-WW I.

Gary Gillman said...

I did a little searching around:

Item: an 1847 scientific paper described the challenges of ensuring sweet casks for brewing purposes:

Of the numerous methods described, none involved coating with pitch or tar. All involved some type of wet or dry heat or mechanical operations (scraping, brushing). Use of some chemicals was described but deprecated.

Item: Lloyd Hind at pg. 843 discusses use of pitched casks in relation to casks used for lager. I only had partial view online and could not glean further details. Ron, I think you have this text and the always-thorough Lloyd Hind may give the final answers for England.

Item: In Roger Protz' Ale Trail, Roger mentions use of plastic liners for modern metal and wood casks. Again I only had a partial view and cannot see the full discussion. Possibly he was referring to the practice only of some brewers. (I have this book but cannot readily find it). I mention this because it would be good to know the contemporary practice and contrast it with the former.

My theory is that the lightly bittered (relatively) lagers of Europe could not stand the least acidity. It was felt better to keep the beer away from the wood. If, as appears the case, a slight taste of tar got into the beer, this was felt preferable to acid taint. Indeed, there is evidence drinkers came to associate a faint taste of pitch with lager beer. George Ehrets states this in his well-known book on American brewing written in the latter part of the 1800's.

But for its part, English bitter ale and porter were much more bitter than lager. Not only that, acidity was an accepted part of the palate of porter and stored ales. I think the English simply had a higher tolerance for acidity and the beers bore it better than for light delicate lagers.

It makes sense to me indeed that some modern casks (wood or other) are lined. Because, modern bitter ale and other beers are hopped much less than formerly. The cleanliness of such casks is probably more critical to palate that 150 years ago. Not that the problem wasn`t taken seriously then, as we see from the 1847 paper delivered in ``Leicester-square``.


Adrian Avgerinos said...

Great stuff! I'm surprised more commentary wasn't made in regards to the flavors imparted by the pitch. How did everything not taste like Retsina?

Martyn Cornell said...

Beautiful typo there, Ron:


Ike said...

I've just been reading a nice book about coopering called 'The Cooper and his Trade' by Kenneth Kilby, written in 1971.

Ken had been a cooper all his life, as had his family for generations back.

This is what he wrote about cask linings.

"The inside shaving was very important with casks used for beer; no rough patches had to be left to provide traps in which bacteria could lurk and turn the beer sour.

…… mild and popular beers had become progressively weaker, and because of the this the danger of bacterial infection increased and made the job of shaving the inside of the cask more important.

Before the first Great War, when the popular beers and stouts were brewed strong, some casks were actually pompeyed, that is charred inside during the firing process, in order to allow the beer to matured more effectively in the cask."

Graham Wheeler said...

I suspect that this was also happening in Britain in some areas. The knowledge that Barclay were pitch-lining their casks by 1922 shows that the concept was not unknown; besides, the Royal Navy were not insignificant users of pitch, so the stuff would have been easily available from before the days of the Spanish Armada.

However, we have a difference in tradition between Bavarian and British brewing. One assumes that at the time of the quoted references, particularly Booth, the Bavarians brewed all their beer during the winter, stored it in their cellars and caves for most of the year before sending it out. Basically, their casks were one-trip containers; used about once a year. When the casks were returned to the brewery they were re-pitched before the next season's brew.

However, pitch-lined casks would be troublesome for multi-trip casks because the lining is so fragile. The lining will not withstand rough treatment by draymen; will not withstand steam or hot water sterilisation, will not withstand abrasive scouring for cleaning, and so on.

Resin-lined casks, if they ever were popular in Britain, became increasingly impracticable from the beginnings of porter through the whole Victorian period as more and more beers became running beers. The casks were back in the brewery for refilling within a few weeks of going out.

It is significant that the 1922 record of Barclay pitch-lining their casks is for export stout. The casks for export beer do not come back home; they are effectively a one-trip container. No doubt Barclays used casks for export that were towards the end of their working life and lined them for safety.

I would suspect that the traditional British pretreatment of new casks before use was superior; that is, scolding them with frequent charges of boiling water for a couple of days to de-woody-flavourise and deodorise them; planing the interiors smooth and then scorching them with a flame to seal the surface.

The type of wood that the casks were made from could be significant. Perhaps the wood used by the Bavarians was considerably more porous than the Baltic oak used by the British, and had to be lined.

Anyway, methinks that you would either have to go back a long way into history or concentrate on very small, very old-fashioned regional breweries to find pitch-lined casks to be particularly standard in Britain.

Ron Pattinson said...

Graham, some very good points there. British and German brewing practices were very different in the 19th century.

I'd not really considered how much more British casks got thrown around. In the classic sommerkeller way of serving, the only trip the cask would make would be from the brewery to the Keller, where it would sit for possibly several months before being tapped.

Though things would have been quite different for Winterbier, which was tapped pretty young.

Come to think of it, the whole no brewing in summer bit must have forced Bavarian brewers to have a much larger stock of casks than a British brewery of the same size.

Ron Pattinson said...

Ike, good quote. Sounds like pretty solid evidence for British casks being unlined.

Gary Gillman said...

Paraffin wax lining was used by some British brewers, at least for some purposes, here export of Burton beer to India:

Scally of Burton-on-Trent patented a process to line beer casks with it. There was a substance in English commerce known as "brewers paraffin", in fact.

To what extent it was widely used is hard to say but it seems some brewers at least used it to coat their casks and other wooden vessels.

This source is a plea in England to use paraffin for this purpose:

This does not prove any empirical use but shows the matter was under discussion and with the first source, suggests some brewers used the process.

The reference to coopers being satisfied with an "acid smell" shows what I suggested earlier: an acid note in English beer was considered normal, even apparently desirable. With big-bodied or big-hopped beers, probably again the effects were not noticed or even considered salutary. The English palate had a complexity, starting with top-fermentation itself, that the new industrial lager wanted to eschew almost by definition. But once again, lighter beverages would have dictated the same approach, ultimately. And they did: modern casks are either lined with a lacquer of some kind or a high-grade stainless is used which needs no lining. As for the surviving wood casks, most surely use a plastic or other lining of some kind. H.P. Harris' notes above show the many traps of using plain wooden containers.


Unknown said...

In doing some research on this topic, I found this article (1922, I believe), which suggests the at least somewhat common use of cask lining during WWI, in part in order to "fix" the problem of spoiled unlined casks due to poor cellarmanship, or, really, due to what I suspect to be slow sales of certain beers, since at the brewery at which I work, that's the key driver of cask beer death-by-oxidation, not so much a lack of care.

In any case, the comparison between various pitch varieties among countries implies, too, that there was a market for the stuff in the UK

Ron Pattinson said...

Hi Unknown,

very interesting article.

It aounds like the lining was mostly to keep the beer away from American oak. Brewers hated the flavour it gave to beer. Coopers would have struggled to sell casks made from American oak if they hadn't been lined.