Fermentation at Carlsberg in the 1880's

I was dead excited at getting a look at one of the notbooks in the William Younger archive. The one recording a visit by employees of the Edinburgh brewery to Carlsberg's breweries in Copenhagen.

I already knew a little of the links between the two breweries. Carl Jacobsen, son of Carlsberg's founder served an appreenticeship At William Younger in the late 1860s.

The notebook has some dead handy description of the equipment and brewing processes at the three Carlsberg breweries. Dead handy, because I have brewing records from Ny Carlsberg.

"Regarding the cooling of the wort they use Rileys vermicular?? refrigerator in each of the breweries, in Carlsberg they cool one with a solution of glycerine, and the other with a solution of brine, these solutions are in their turn cooled by a powerful Picket ice machine to 19º F (13º F below freezing point then used in the refrigerator and so on continuously. The wort is cooled to 43º F and run to the fermenting tuns.

These tuns are filled from below through a two inch pipe running below the length of tuns. When the wort is near finished running through the refrigerator, the supply of cold liquid is stopped this is to prevent the wort freezing in the pipes."
"Notes of a visit to the breweries of Messrs. Jacobsen Senr. & Junr. Copenhagen Sept 1881." held at the Scottish Brewing Archive, document number WY/6/1/1/11.

That's a much cooler temperature than in British breweries, where yeast was usually pitched at around 60º F, and never lower than 55º F. No need to worry about the wort freezing in the pipes at those temperatures.

"The requisite quantity of yeast is added at once to the wort in the proportion of one pound per barrel. (This result is calculated from the figures given by Mr. JKoehler the manager of Old Carlsberg - viz. 10880 litres of wort get 60 Danish pounds of yeast when pitched at a temperature of 43º F. 163 litres is equal to one barrel of 36 Imperial gallons.) For the washing of the yeast see Mr. Stenhouse's notes.

When the worts are all run into the tuns, the wort pipe is flushed with hot water, then thoroughly steamed out, and again flushed with warm water. This treatment is again repeated previous to running fermented beer or wort through them. They have a provision to save the connections from the tuns to the wort pipe. This is simple and also effective. It consists in shaping the pipe lying between every two tuns into an arc of a circle. The ends of the arc terminate at the cranes in the tuns. By this arrangement the pipe instead of expanding in a lateral direction expands between every two tuns very much like a bow."
"Notes of a visit to the breweries of Messrs. Jacobsen Senr. & Junr. Copenhagen Sept 1881." held at the Scottish Brewing Archive, document number WY/6/1/1/11.

A pound of yeast per barrel of wort is about the same as British breweries used. 10,880 litres is about 66 Imperial barrels. So not a huge amount of beer by UK standards.

They seem have been very particular about cleanliness at Carlsberg.Which is no bad thing.

Some more about the fermentation itself:

"The fermentation just now lasts nine days and is not skimmed until near the emptying of the tun. Previous to filling the lager casks the beer is run to an intermediate settling tun where it lies some time - these tuns hold three to four fermenting tuns. In cleaning a fermenting tun the yeast is carefully removed as far as practicable in a flat oblong vessel. Another similar tub is put below the tun and the yeast which could not be gathered off the sides and bottom of the tun is washed with a minimum quantity of warm water into the tub. A few gallons judiciously applied is sufficient for this purpose. This water is carried out of the fermenting room and emptied into the common drain. When the tuns are partly washed in this way the cranes are opened which lead to the pipes running the whole length. The tuns are now thoroughly washed with warm water, this water being at once let into the tun room drain. When all the tuns in a row have been washed, the pipe is flushed with boiling watersteamed and again flushed."
"Notes of a visit to the breweries of Messrs. Jacobsen Senr. & Junr. Copenhagen Sept 1881." held at the Scottish Brewing Archive, document number WY/6/1/1/11.

Nine days seems pretty quick for something pitched at 43º F. Interesting that the wort didn't go straight into the lagering vessels at the end of primary fermentation. It sounds to me as if the sttling tun is playing the same role as cleansing vessels in a British brewery: getting rid of most of the yeast.

Next time we'll learn how Carlsberg kept their fermenting wort cool.