hist-brewing: RE: sanitizing wooden casks

Mike Bennett mjb at efn.org
Tue Apr 27 17:50:23 PDT 2004

> -----Original Message-----
> From: "Charles Lauder, Jr" <CNJ at lauder-mander.fsnet.co.uk>
> To: <hist-brewing at pbm.com>
> Date: Tue, 27 Apr 2004 09:42:35 +0100
> Subject: hist-brewing: wooden cask
> I've acquired a 5-gallon wooden cask from an antiques fair. The
> seller didn't know whether it was used previously for sherry or
> beer, or even wine. I intend to use it for beer. I've been
> filling it full of water to expand the wood to minimise leakage when I
> later add the beer--so far this seems to be working: each new
> fill-up of water involves less and less leakage. Other than that, does
> anyone know how to treat/prepare a wooden cask for storage of
> ale? What sort of steriliser is recommended?

Being a 5-gallon cask, there is a BIG difference in the surface-to-volume
ratio from that of a Barrel or Tun.  You may get excessive leaching of
tannins and other flavor compounds from the wood.  I suggest that you taste
the water every time you fill it with water.  If there are off flavors, or
you can't stop all the leaks, you'll need to seal the cask using "Brewer's
Pitch".  You can find several places on the internet that stock it (last I
checked).  Otherwise you can use beeswax or paraffin wax to seal it.  Wax
has a tendency to melt and wash out when cleaning the cask with hot water
though.  I've never done it, but you might try a food-grade epoxy sealant as
a last resort.

As far as sanitizing (sterilizing is NOT possible with a wood cask), the
thing to remember is:

***   Because of the porous nature of the wood, ANY    ***
*** sanitizer or cleaner that you use will be absorbed ***
*** by the wood and unless you rinse EXTREMELY well it ***
***            will leach into your beer.              ***

Therefore my choice for sanitizing is either PEROXYACETIC ACID (not normally
available to home brewers) or OXINE.  Both sanitizers degrade naturally
(within a few hours) into inert by-products that won't harm the beer.
Follow the directions for these sanitizers TO THE LETTER.  They are probably
the best out there, but if used without the proper precautions can be
extremely hazardous.  Stay away from Chlorine or Iodine products.

For general cleaning, nothing beats HOT (180F+) water and a cleaning brush.
I know working through a small bung hole isn't the easiest thing in the
world, but sometimes it's the best way.  Use an inspection mirror to make
sure you don't miss anything.  If you must use chemicals, try baking soda
(Sodium Bicarbonate) in a 5% solution or as a last resort, a caustic (sodium
and/or potassium hydroxide) cleaner.  Make sure to rinse extremely well with
HOT water.  To make sure you've rinsed well enough, test the pH of the rinse
water.  It should be neutral (~ph 7.0).

I can't say this clearly enough.  SULFITES ARE FOR WINEMAKERS.  DON'T USE
THEM!!!  Sulfites are anti-fermentive NOT anti-bacterial.  They do NOT kill
bacteria and yeast, they just inhibit their growth.  They inhibit growth so
that the wine yeast can "take center stage" and become the "dominant" player
in the fermentation.

When a wine maker cleans a cask they're mainly interested in removing the
lees and sludge at the bottom of the cask.  When compared to a brewer,
they're not as concerned with sanitizing because the wood often contains
beneficial microorganisms too.  That's not to say that vintners aren't clean
freaks too.  But they also know that the alcohol/pH levels of most wines are
sufficient to keep wine-spoilage organisms/wild yeasts at bay as long as
they don't get a firm foothold in the barrel.  Hence the use of sulfites
both in the must, and in the barrel cleaning regimen.

Beer, on the other hand, has MUCH higher residual sugar levels and lower
alcohol levels (in general).  It is a MUCH more inviting and hospitable
place for those yeasts and bacteria that were only stunted from the use of
sulfites.  Lambics and Sour ales aside, brewers want the beer yeast to be
the ONLY player in the fermentation.  Therefore, brewers need to make sure
that all beer-spoilage bacteria is eradicated not just stunted.

Mike Bennett
Head Brew Dude, Southside Speakeasy, Salem OR
Recognized BJCP Beer Judge
[1958, 287.1] Apparent Rennerian

....Give a man a beer, he'll waste an hour.
Teach a man to brew and he'll waste a lifetime....

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