Over 100 years many changes have occurred in beer and brewing. Two great innovations have roots in the early 1900s and are still vital today.
One is pure yeast culture. Its father is the Danish chemist Dr. Emil Hansen. He developed a reliable method to isolate a single strain of yeast from the “mixed” cultures which had evolved empirically in breweries and distilleries. This promoted better control of fermentation, and a predictable, acceptable flavour.
The other great innovation, whose historical importance is rarely mentioned in consumer beer literature, is the invention of temperature-controlled, closed fermentation. Dr. Leopold Nathan, a Swiss inventor, devised this system prior to the First World War.
He had technical training of some kind but was not a graduate engineer, to my knowledge.
He invented a cylindrical fermenter with a conical base, equipment used in any scale of modern brewing from brewpub to industry behemoth. While not every brewery uses it, it is fair to say most do.
The system was slowly adopted in the English-speaking world, and finally on the Continent. Between the two world wars Australia was a cradle for its implementation via Peter Hay, who founded the Richmond Brewery.
The Nathan system was initially felt suitable only for lager production. After testing in Britain before the war, still at the time a stronghold of ale (top-fermentation), the Nathan system made steady advances, post-World War II. See D.R. Maule of Whitbread Brewery in his absorbing article, “A Century of Fermenter Design” (1986).
Maule explains a multiplicity of fermentation systems was in use at the end of the 1800s, empirically-developed and often regionally-defined.
These were i) Yorkshire stone square, ii) the skimming system, iii) dropping system, iv) Burton Union system, with linked open casks to vent excess yeast, and yet more.
Today, some small brewers still use flat- bottom fermentation, closed or open, but conical systems have mainly taken over, even in Belgian brewing. The classic Trappist brewery Chimay has used them for decades, for example.
“Continuous fermentation” is the other main modern method system. This is a complex of linked tanks that operate for months until shut down for cleaning and maintenance. This method makes them suitable for producing one beer, or one main brand. Guinness uses this system for its famous stout.
Nathan’s invention permitted wort to be fermented and conditioned (clarified, carbonated) in a couple of weeks, vs. three to four months, maybe more, for lager traditionally. Closed fermentation meant the beer was beyond the predation of airborne organisms that might turn it, or impart off-flavours.
The CO2 was not lost to the atmosphere as in open tanks, but was (or could be) vented in a controlled way, “washed” of its funky “green” flavours such as dimethyl sulphide, and re-introduced to help fizz the beer.
The use of close temperature control permitted “cold crashing” to obtain clarified beer months ahead of the traditional schedule.
Maule explained that Nathan’s system gained traction in the U.K. particularly after C.I.P., or cleaning-in-place, was adopted.
Nathan’s basic design, a reproduction is shown by Maule, continues virtually unchanged today. One newer element is the unitank variation, where the beer conditions completely in the fermenter vs. being transferred to a separate brite tank, as it’s termed.
Unitanks are often useful in brewpubs, where space is at a premium. Breweries that want a noticeably clear beer generally use a brite tank. This permits also more storage capacity, and better utilization of fermenter capacity.
Who was Leopold Nathan? He was a German-born Swiss national, active from about 1900 until the 1930s.
Nathan is a titan of modern brewing, as attested by the longevity and reach of his system for almost any kind of beer, at any scale, anywhere in the world.
He deserves to be better known, as the good taste and reliable quality of modern beer owes so much to him.