Beer Brewing Yeast
In the Finnish folk epos Kalevala, a rather detailed and colorful description of how beer appeared is given. So, during the creation of the world’s first beer, the heroine of the poem Osmotar experienced certain difficulties in starting the fermentation process, until the bee brought her the necessary fermenting ingredient. Hearing that Klaus Christensen, founder of Munkebo Mikrobryg and her main brewer, collected wild yeast carried by bees, I could not help but draw an analogy with this epic piece. This story tells how wild yeast was used to ferment beer.
In nature, yeast surrounds us everywhere. Most often they are concentrated in places that are a source of sugars, such as fruits, berries and tree bark. Therefore, collecting yeast with the help of bees makes sense, because bees prefer precisely those places where wild yeast is present.
Nevertheless, the process of collecting yeast in nature is not an easy task. In the vicinity of yeast, rich microflora “lives”, represented by a variety of bacteria that are extremely undesirable for brewing. Even if you manage to separate the yeast from these microorganisms, finding a suitable strain for a particular beer style is a real lottery, because the yeast should effectively ferment the sugar from the malt and give a tasty drink at the exit.
Klaus was born on the Danish island of Funen, where his grandmother brewed traditional farm ales. His family even used their own yeast strain, which was great for producing farm ale, which, however, was lost in the 1950s. One fine day, Klaus decided to return to his roots and get a yeast strain for farm ale. He possessed a degree in healthcare and experience in research in the field of cytology and molecular biology, undoubtedly helped him in his work on the project.
Klaus bought several bees from a beekeeper’s neighbor. He placed them in Petri dishes where the bees left the bacteria they carried. In addition, a selective nutrient medium for yeast growth was added to the cups, which is suitable for the production of beer with a high alcohol content and hop bitterness.
After two and a half years and hundreds of experiments, Klaus managed to obtain four strains of pure yeast cultures, ready for use in brewing. These strains, called Munkebo, numbered 001 to 004, create a wide range of fruit flavors and aromas. So, No. 001 and No. 003 add banana notes, No. 002 is responsible for raspberry-cherry tones, and No. 004 forms peach and apricot shades in a bouquet. White Labs labeled these yeast cultures as Saccharomyces cerevisiae, which includes baker’s and brewer’s yeast. When Klaus suggested that the old-timers on the island of Funen taste the ale created by him based on strain No. 004, they said that his beer tastes like the same farmer ale that his grandmother once brewed.
Today, the brewery Munkebo Mikrobryg ferments its ales Hjemstavn Ale (5% ABV) and Hjemstavn Stærk Dansk Ale (10%) using strain No. 004. The “bee” yeast obtained by Klaus has a very delicate fruity character, which, in my opinion, is the best transmitted in ale by 5%. Amber Hjemstavn Ale is a strong malt ale with subtle but distinct notes of apricot created by the yeast used, as well as tones of iris, hay, black pepper and sea salt. Hjemstavn Stærk Dansk Ale is an excellent beer, in which the bright malt component unobtrusively interrupts the yeast character.
Mads vindfeld andersen
Klaus shared with me samples of his strains No. 002 and No. 004, which I tested in practice, brewing beer on their basis. At first I used them to ferment Finnish a la farm ale, which I cooked according to my own basic recipe for sahti, with the exception of the yeast portion (one half of the batch with No. 002, the second half with No. 004). In my opinion, the yeast should have worked well at fairly high temperatures, which is why I fermented my ales at 24 ° C in a manner similar to the way Hjemstavn Stærk Dansk Ale was fermented in Munkebo. The yeast really did not disappoint, and at the end I got soft ales with a sweet malt taste and deceptive nutrition (with a strength of 8–9 degrees).
According to the tradition of consuming farm beer typical of northern countries, I served the ales I received with freshly prepared literally a week after brewing. I must admit, I was amazed at how soft the alcohol component in version No. 004 was from the very beginning: it completely lacked pronounced or harsh alcoholic notes. Therefore, this yeast strain is an ideal fermenting component for strong beers. Yeast No. 002 gave a certain alcoholic harshness to the taste of the drink, which gradually leveled off. At first, the refreshing malt character drowned out fruit tones, but a month later light notes of apricot began to appear in No. 004, while in No. 002