Beer Brewing Guide - Step 6: Fermenting
Reading time: 4 minutes
Fermentation is one of the most fascinating and crucial steps in beer production. At hobby brewer scale, you can take control of the entire process to make your own craft beer. In this text we will look in detail at fermentation, including primary fermentation and secondary fermentation in bottles or kegs, and explore the background to this fascinating process.
Background to fermentation
Fermentation is the process by which yeast converts the sugars contained in beer wort into alcohol and carbon dioxide. This biological process is crucial to beer production and significantly influences the flavour, aroma and texture of beer through the formation of fermentation by-products. There are two main types of fermentation: primary fermentation and secondary fermentation or storage of the beer.
Primary fermentation:
Step 1: After the wort has been transferred from the boiling process to the fermentation vessel, the first step of fermentation takes place: the addition of yeast. The choice of yeast has a significant influence on the flavour and aroma of the beer. It is advisable to choose the yeast to suit the style of beer. Yeast can be added in the form of dry yeast or liquid yeast. The quantity depends on the manufacturer's instructions. The yeast starts converting the sugars into alcohol and carbon dioxide after about a day.
Step 2: During primary fermentation, the yeast ferments the sugar in the wort. This process usually takes several days to weeks, depending on the type of beer and the yeast used. During fermentation, the temperature usually rises slightly as the yeast is active.
Step 3: During primary fermentation, it is important to monitor the temperature and the progress of fermentation. Too high a temperature rise can produce undesirable flavours, while too low a temperature range will put the yeast to sleep. Refer to your beer recipe or yeast pack for the recommended temperatures. Primary fermentation is complete when the yeast has fermented most of the available sugars.
The green beer must now be transferred to a pressurised container to build up carbon dioxide. It can be left to ferment in the bottle or in a barrel.
Secondary fermentation:
Step 1: Once primary fermentation is complete (when no more bubbles have risen in the bung tube for around three days), the beer is separated from the yeast and trub deposits. If nothing has happened, you can add some yeast for secondary fermentation. There are special yeasts for bottle conditioning, such as CBC-1.
This is done by carefully draining the clear beer into a separate container. The remaining yeast and trub cake can be disposed of. It can also take place directly from the fermentation tank into the bottle or keg.
In any case, make sure that the first shot from the tap is disposed of with a lot of trub and that the container has stood still for a long time beforehand so that a stable sediment is formed which can be drawn off cleanly. The lid should be opened slightly beforehand so that pressure equalisation can take place. The decanting or bottling process must always be completed before the young beer has reached the brewing stage.
Secondary fermentation in the bottle:
Step 1: Thoroughly clean the bottles under 60°C hot water. We recommend 4g/L of PuroOxi for this.
Step 2: Add a small amount of sugar (approx. 7g/litre at room temperature for most beer styles) to the clean bottle to enable secondary fermentation. We recommend our carbonisation drops.
Alternatively, approx. 5% of the wort can be collected in a bottle after boiling and then frozen. As wort is very susceptible to infection, it must be frozen to prevent the start of fermentation. This "food" can be defrosted on the day of bottling and added to the young beer to be bottled instead of sugar (ensure good mixing).
During secondary fermentation, the sugar will bind the resulting carbon dioxide in the beer under pressure. Use a filling tube to fill the bottles from the bottom to the top with minimal foaming.
Step 3: Close the bottle with a clean crown cap or swing top. We recommend our O2-absorbing crown corks and the Corona cork stopper.
Step 4: The bottles are usually stored warm for a fortnight to allow the carbon dioxide to form. Use a MattMill bottle manometer on one of the bottles to be filled to check the success of the carbonation. The beer can then be left to mature in the fridge for a further two weeks. During this time, the flavours develop and the beer becomes clearer. It is better to place the bottles upright in the fridge so that the yeast sediment collects at the bottom of the bottle and remains behind when the beer is poured later.
Secondary fermentation in pressurised kegs:
Step 1: If you opt for keg fermentation, the clear beer is transferred to a KEG keg, for example. Here, the carbon dioxide is produced under pressure from the residual sugar of the green beer or by adding sugar or food.
Step 2: The beer remains in the pressure keg to mature while it carbonises and develops a fine beer bouquet. The time the beer spends in the keg can vary depending on the beer style.
Completion of bottle and keg fermentation:
Once the beer has matured in bottles or KEGs, it is chilled to allow finer beer flavours to develop through maturation. The beer can then be served and enjoyed from the bottles or KEGs. In either case, the yeast sediment collects at the bottom, which should be disposed of as the first shot in the KEG and left as the last sip in the bottle.
The importance of fermentation:
Fermentation is not only the process that produces alcohol and carbonation in beer, but also the one that gives beer its unique flavour and texture. The choice of yeast, the fermentation temperature and the duration of fermentation are all decisive factors that influence the character of the beer. Hobby brewers have the opportunity to control these factors and create individual beers according to their preferences. Fermentation is therefore a key aspect for those who want to delve into the world of beer brewing.
| Brewing Bucket 25L | Apollo 30L Snub Nose | Easybrew Fermenter 30L | Grainfather Conical Fementer 30L | Speidel Conical Fementer 30L |
Temperature control | X | X | ✓ | ✓ | ✓ |
Option to adjust the temperature |
X
| X |
X
| ✓ | ✓ |
Pressure fermentation | X | ✓ | X | ✓ | ✓ |
Height and diameter | 36cm x 38cm | 72cm x 38cm | 58cm x 35cm | 91cm x 36cm | 83 cm x 35 cm |
Price | 10,95€ | 129,95€ | 169€ | 649€ | 995€ |
Braumarkt Beer Brewing Guide
Step 1: Malt Milling
Step 2: Mashing
Step 3: Lautering
Step 4: Boiling
Step 5: Whirlpool & Cooling
Step 7: Bottling
Step 2: Mashing
Step 3: Lautering
Step 4: Boiling
Step 5: Whirlpool & Cooling
Step 7: Bottling