Beer Brewing Brief Info – infusion / decoction

Beer brewing is here around for some 3.000 year, depending on mashing and fermentation method there are 2 basic kinds of beer:

  • bottom-fermented beers (Lagers, Pilsner, Bock)
  • top-fermented beers (Ales, Stouts, Porter, Weizen)

Our microbrewery equipment allows both beer brewing methods.

Bottom-fermented beer brewing (Decoction Method)

Brewing (Boiling):

Time: depending on style, beer brewing take 7-10 hours

a) Mashing – Mixing of grist with water at 37°C in hydrator and in kettle for 25 minutes

b) Mash Boiling

  • Mash is heated in brew kettle to 52°C for 15 minutes and at this temperature for the following 15 minutes, inducing the splitting process (proteins and starches).
  • Lower sugar transforming temperature-mash is heated from 52°C to 62-64°C, starch, via enzymes, is divided into maltose. Part of mash is transferred to combi-tank for 20 minutes.
  • Higher sugar transforming temperature-mash is heated from 64°C to 72-75°C for 15 minutes and remains at this temperature for the following 25 minutes. Starch, via enzymes, is transformed into maltose. Further heating of mash to 100°C for 30 minutes, and then boiled for 25 minutes.

Scheme of Decoction Mashing
decoction beer brewing method temperature graph

c) Lautering – The rest of the mash goes into the brew kettle at 100°C. Then is transferred to the lauter tun, where the remainder of the mash is kept at 64°C. By mixing these two parts, the final mash temperature in the lauter tun is 75°C.

  • Leave (resting) at Lautering temperature 73-75°C, sedimentation in combi tank for 30 minutes.
  • Lautering – sugar extract (wort) is filtered through the boiled mash from combi-tank to brew kettle for 30 minutes.
  • Sparging (washing out of sugars remaining in spent grain) – layer of grain in lauter tun is sparged with water at 75-78°C. The sweet wort is leached out and lautered in brew kettle for 30 minutes.

Wort boiling:

Wort is heated in brew kettle to 100°C. During the 90 minute boiling process, hop granules and hop extract or other additives are added.

Wort Cooling:

a) Whirlpooling – (sediment is separated) – wort is stirred in brew kettle by bottom attached mixer paddle, which gradually comes to a stop.
Separation of sediments from Wort prior to Wort cooling (performed in BKW-Tank).
Wort is put in whirlpooling motion by agitator (Agitator is frequency changer controlled). After obtaining maximum rotating speed, paddle gradually slows down till it comes to a complete stop. This allows the sediment to settle on the bottom of the tank. In the tank bottom is placed DN 50 outlet for Wort transfer and DN 65 outlet for sediment removal.
b) Wort Cooling – 60 minutes in heat exchanger.

Fermentation and Maturation (28 days):

  • Cooled wort, at fermenting temperature 6-9°C, is fermented with yeast with the ratio 0.5 L Yeast: 100 L wort (bottom fermentation).
  • Main fermentation takes place at 9-16°C. Fermentable sugars in wort are changed to Ethanol, CO2 and heat. At the end of the main fermentation, it is necessary to lower the heat.
  • Maturation – 0° to -1°C at 1.2 Bar pressure. Green beer absorbs CO2 and forms flavor (beer acquires distinct taste and fragrance).

Top-fermented beer brewing (Infusion Method)

This is the simplest brewing method. Beer brewed this way is lighter in color and has less distinctive flavor than beer brewed by decoction method (no mash transfer takes place). Therefore, the infusion method takes app. 60 minutes less time to do. Processing of grist, with high enzymatic activity, is of great importance. It is important to support contact of enzymes and wort by continuous mixing.
Mashing is done at 60° – 62°C, then remains at that temperature for 30 – 40 minutes. Then heat to 72°C, and keep for 20 minutes. Heat to Lautering temperature (76°C), staying for 20 minutes.

Scheme of infusion mashing
infusion beer brewing method temperature graphThe next step – Lautering, whirlpooling is the same as with decoction method.
For fermentation process, yeast is used with top fermenting.
Fermentation and Maturation takes here 21 days.