Cooling Off: Or, Wort is Cool(ed)


It is still cold here in Toronto. As I am not a cold-weather creature, this does not make me happy. However, I did wonder if it would have made nineteenth-century brewers happy—would the extra-long winter have meant an extra-long brewing season for them?

You see, for small, rural brewers, brewing tended to be more of a seasonal activity. This was mostly because you have to cool wort before adding the yeast. After all, when the wort comes out of the brew-kettle it is boiling. Yeast is a living organism. If you chuck it into boiling hot wort, it won’t be living much longer, which means that it will not be fermenting anything terribly effectively.

All of which to say: brewers needed some way of cooling the wort. In the first half of the nineteenth century, they used coolers. W. Stewart describes them as “floors of wood, surrounded with a wooden ledge, placed in the most airy and exposed situation in the brewery…in large breweries, they are of an enormous extent” (Stewart, 63).

The idea behind a cooler is to spread the wort out very thinly over a wide surface area in order to let the heat dissipate. That’s why coolers can be so expansive—they’re usually only 2-4 inches deep, so they need to be quite wide to contain a large volume of beer.

Our cooling ship, located on top of the casks - so, a slightly different set-up than the larger breweries.  (Courtesy www.greatcanadianbeerblog.com)
Our cooling ship, located on top of the casks – so, a slightly different set-up than the larger breweries.
(Courtesy http://www.greatcanadianbeerblog.com)

So, no problem, right? Run the beer into the cooler and wait.

Not quite.

Beer fresh out of the brew-kettle is extremely vulnerable to contamination. Remember, it’s been at a rolling boil for a significant amount of time (usually an hour, for us), which means that it’s been rendered more-or-less sterile. The longer the wort is left out in the open, the more likely it is to be infected by airborne pathogens or wild yeast. Brewer Thomas Hitchcock also worries about the “acidifying” of the wort through the absorption of excess oxygen, which apparently “takes place most rapidly in warm weather” (Hitchcock, 31).

Modern-day breweries have heat exchangers which can cool the wort very quickly. Victorian brewing guides recommend getting it down to anywhere from 11-20 degrees Celsius. From boiling, that’s quite a drop, especially in the summer—without air conditioning to help.

So how did they do it?

Some brewers avoided summer brewing altogether. According to A Practical Treatise on Brewing (1835), by William Chadwick, “…in hot weather, brewing is a critical operation, and private families should refrain from brewing in summer if possible…no prudent person would willingly brew when the temperature of the air is as high as 60 degrees” (Chadwick, 43-44). In the winter, however, it would be easy to open a window (Stewart does recommend letting a fresh air current pass over the wort) and let that chill Canadian winter help with the cooling.

But for large commercial brewers, sitting out the summer months entirely wasn’t always an option.

Stewart’s brewing guide addresses the conundrum of summer brewing:

When the brewery is obliged to make ale in warm summer weather, it is material to reduce the temperature as low as possible. In such cases great advantage would attend cooling the wort in coolers without any roof or covering whatever, but quite open to the sky; because in clear nights, the wort might be cooled in this way, eight or ten degrees lower than the temperature of the atmosphere… (Stewart, 66-67)

The idea seems to be that the wort would radiate the heat out into the night:

We have no doubt that it might be put in practice with advantage in hot climates; at that, by means of it, good ale or porter might be manufactured in the East and West Indies. Such a manufacture, if successful, would be particularly relished in India… (67)

Of course, this was only a theoretical model. There were other options. While Chadwick urges private families to avoid warm-weather brewing, he notes that the commercial brewer generally “…also has a command of cold spring water, that can he convey through pipes, so contrived to branch in various directions amongst the worts, that they are cooled down to the required temperature in a very short time” (42).

Which is one reason why breweries were often located near streams. It’s pretty similar to what we do at Black Creek: we have pipes branching through our cooling ship, although we use Toronto tap water.

Bloor, Joseph, brewery, n. of Bloor St. E., between Mount Pleasant Rd. & Sherbourne St.
Joseph Bloore’s brewery, located on the stream running through the Rosedale ravine. (courtesy http://www.torontopubliclibrary.ca)

 

By the century’s later decades, cooling had become more reliable. E.R. Southby’s A Systematic Handbook of Practical Brewing dates from 1885, and mentions refrigerators. Don’t get too excited—they weren’t fridges, but rather, three distinct set-ups:

  • Wort flows in a body over pipes placed horizontally.
  • Wort flows in a film over pipes placed vertically.

OR

  • Wort flows through pipes surrounded by cool water.

Southby favours the vertical model, particularly recommending the Riley or Ashby models—reminding us that brewing was becoming increasingly industrialized. The old coolers were still used to aerate the wort—but rather than the old wooden models, cast iron or copper (like ours!) were preferred, as they were easier to clean and didn’t rot. Still, cooling was increasingly based on the principle of heat exchange, much as it is today.

So, would a small, country, one-man brewing operation enjoy this cold snap?

But I’m still looking forward to May and warmer weather!

– Katie

Sources:

Chadwick, William. A Practical Treatise on Brewing. London: Whittaker and Co., 1835.

Hitchcock, Thomas. A Practical Treatise on Brewing. London: R. Boyd, 1842.

Southby, E.R. A Systematic Handbook of Practical Brewing: Including a Full Description of the Buildings, Plant, Materials and Process Required for Brewing All Descriptions of Beer. London: E.R. Southby, 1885.

Stewart, W. Brewing and Distillation, with Practical Instructions for Brewing Porter and Ales According to the English and Scottish Methods. Edinburgh: Adam and Charles Black, 1849.

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