High Tech Brewing

          by Mike Retzlaff

Today, we tend to think of high-tech in brewing as big control panels with meters, lights, gauges, switches, and such; almost like a nuclear power station.  The big breweries utilize equipment such as computer controlled pumps and valves, fermentation vessels with ethylene glycol cooling systems, automated high speed machinery for bottling, canning, and kegging, etc.  They utilize sensors on almost every piece of equipment to monitor all aspects of brewing.  However, the concept of “high-tech” depends upon your point of view.  Many of us can remember the TV and magazine ads which referred to their products and services as “jet age” or “space age”.  Those monikers don’t grab the same attention anymore.

The thermometer was developed over a period of years.  The first thermometer resembling its present form was made in 1654.  Fahrenheit developed his instrument in 1724; Celsius developed his in 1742.  The thermometer, as a brewing instrument, was starting to be found in general use by 1760.  The hydrometer was first marketed to brewers in 1768 and was widely accepted by the 1780’s.  Both of these instruments were “high-tech” in their day – now they are commonplace.

There is plenty in print of the early brewers and the societies in which they lived.  In contemplating what they did, I wondered how they did it.  There must have been some way they could perform all the tasks involved in malting, mashing, brewing, fermenting, and packaging beer without the basic brewing tools we now take for granted.  They accomplished all this with apparent consistency.

Imagine how you would brew a batch of beer without a thermometer and hydrometer.  It can certainly be done as our predecessors did so for several thousand years without any science or scientific understanding at all.  Back then it was considered “the brewers art.”  Brewing still consists of a lot of “art” but can be accomplished with the purchase of a book instead of a lengthy apprenticeship.  Much of what made brewing an art is now explained through science.   

As home-brewers we often see ourselves as far removed from Coors, Miller, and Budweiser as one can get.  Compared to brewers of just over 200 years ago, we utilize technology they couldn’t even imagine.  We all use thermometers. We all use hydrometers.  Almost all of us use electricity, natural gas, or bottled gas instead of going out to dig coal, cut peat, or to reap firewood from the forest.  So, how did they do it?

The following excerpts give us a window on the past without the use of a thermometer.


“Fail not to boil your water six or eight minutes, then let it into the main tun; if time will permit, do not put your malt in for mashing till the steam has escaped and you can see your face in the water; but if time will not admit of this, add about one gallon of cold water to eighteen gallons of hot.” 1

London method of brewing Stout Butt beer

“ . . . this must be made very hot, almost ready to boil, yet not so as to blister, so then it will be in too high a Heat; but as an Indication of this, the soul Part of the Liquor will ascend, and the Malt swell up, and then it must be parted, look’d into, and felt with the Finger or back of the Hand, and if the Liquor is clear and can but be just endured, it is then enough,” 2

Nottingham method of brewing Ale or October beer

“The first full Copper of boiling Water he puts into the Mash-Tub, there to lye a quarter of an Hour, till the steam is so far spent, that he can see his Face in it; or as soon as the hot Water is put in, throws a Pail or two of cold Water into it, which will bring it at once into a temper.” 3

The Country or private way of brewing

“I will suppose a private Family to brew five Bushels of Malt, whose Copper holds brim full thirty six Gallons or a Barrel : On this Water we put half a Peck of Bran or Malt, when it is something hot, which will much forward it, by keeping in the Steams or Spirit of the Water ; and when it begins to boil, if the Water is foul, skim off the Bran or Malt, and give it to the Hogs, or else lade both the Water and that into the mash Vat, where it is to remain till the steam is near spent, and you can see your Face in it, which will be in about a quarter of an Hour in cold Weather; then let all but half a Bushel of the Malt run very leisurely into it, stirring it all the while with an Oar or Paddle, that it may not Ball, and when the Malt is all but just mix’d with Water, it is enough, which I am sensible is different from the old way and the general present Practice; but I shall here clear that Point.  For by not stirring or mashing the Malt into Pudding Consistence or thin Mash, the Body of it lies in a more loose Condition, that will easier and sooner admit of a quicker and more true Passage of the after ladings of the several Bowls or Jets of hot Water, which must run through it before the Brewing is ended; by which free percolation the Water Has ready access to all the parts of the broken Malt, so that the Brewer is capacitated to brew quicker or slower, and to make more Ale or small Beer.  If more Ale, then hot boiling Water must be laded over so slow that one Bowl must run almost off before another is put over, which will occasion the whole Brewing to last about sixteen Hours.” 4

1   E. Hughes   A Treatise on the Brewing of Beer  1796

2  Wm. Ellis   The London and Country Brewer  1787

3  Ibid

4  Ibid


The Germans, Czechs, and Austrians, among others, utilized decoction mashing.  They would “dough-in” with ambient temperature water.  They would raise the mash temp by infusion to “blood temp” which would be about 99o; they had a very handy comparator at the end of each arm.  Trial and error taught them how long to hold the mash at that temp.  They would use the mash scoop to pull the first decoction.  Over time, they learned how many scoops (thick or thin) were required for each decoction.  The decoction was pulled and stirred while slowly heated in a kettle until it boiled.  It was then returned to the main mash and stirred in.  After some time, a second decoction was pulled and the process repeated.  It was after the thermometer became available that they held the decoction at a rest temp before continuing the heating until the mash boiled. 

The method which preceded the use of the hydrometer is the calculation of “brewer’s pounds” to determine extract.  I have seen SG readings listed to four and five decimal places.  I thought perhaps that commercial brewers have some sort of digital electronic hydrometers.  They actually calculate brewer’s pounds and convert that into SG.

It is a rather straight-forward method.  In Britain, an imperial gallon of water weighs exactly 10 pounds.  A barrel contains 36 imperial gallons.  Therefore, a barrel of water has a net weight of 360 pounds.  A full barrel of wort weighing 375 pounds net would have an extract weight of 15 pounds.  15 divided by 0.36 = 41.67 or 1.04167 SG.  This is how they can figure SG to so many decimal points.  Conversely, a SG of 1.060 would calculate to 60 X .36 = 21.6 brewer’s pounds or a full barrel of 381.6 pounds.

This system was used in breweries and taught in brewing schools even here in the States at least until the time of Prohibition.

In 1990 when I started brewing, you could still buy “red-line” hydrometers.  These had a red line painted on the internal paper scale at the upper end of the stem which would estimate when there was enough sugar left to carbonate your beer.  I have no doubt that these are the very instruments responsible for most of the stories of how “grandpa used to make beer and one day his shed blew up.”  The terminal gravity of any batch is dependent on a number of factors; the least of which is a red line on a scale.

During Prohibition, Hugh F. Fox, secretary of the US Brewers Association and a leading spokesman for the brewing industry, called homebrewed beer “troublesome and messy, and not very successful” and added that one could not produce “a light, palatable, and wholesome brew without the use of highly specialized and costly apparatus and facilities for sterilizing, filtering, and refrigeration.”   

I think Mr. Fox would have a different opinion these days.  When you consider the quality of beer we brew with the less than stellar equipment we tend to use, it seems rather amazing.  Remember, we are all high-tech brewers; at least in the eyes of someone.

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