Today we're going to talk about a few key points to improve the clarity of the beer.
First of all, the turbidity in the beer can be roughly divided into two categories: biological turbidity, non-biological turbidity
Biological turbidity: Biological turbidity is usually caused by the low flocculation and sedimentation of yeast(commonly found in powdery yeast and upper fermented yeast) suspended in the liquor; Or it's caused by wild yeast and bacterial infections.
Turbidity caused by bacterial contamination is easily detected because it causes changes in the flavor and odor of beer. However, once pollution occurs, beer will be difficult to rescue, and only next time improve the disinfection and process level.
Non-biological turbidity: mainly caused by a mixture of protein(malt) and polyphenol/tannin(wheat peel and hops). In addition, the introduction of a large amount of unferable sugar(such as lactose), pectin(common problem of fruit beer), incomplete decomposition of starch(introduction of grain accessories), polymer protein, and granular dry shot in beer can also cause different degrees of turbidity. These types of turbidity can be changed by the brewing process.
Raiders: Points to improve clarity
Choose the right grain.
Although the medium protein improves the taste of beer and the foam of the wine head, the high molecular protein from protein-rich grains(wheat, large cereals, oatmeal) can cause beer turbidity.
If you want to make a clear, light beer, it is best to use two-edged malt and pale malt malt for brewing; Accessories that increase sugar levels can use refined sugar, corn, or rice.
Choose the right yeast.
The flocculation of yeast means that yeast cells gather together to form yeast blocks that can easily separate beer. The high-flocculation yeast will form a yeast precipitate at the bottom of the fermentation tank 3-5 days after the fermentation begins(the fermentation temperature is appropriate).
If you use yeast with high flocculation and fast sedimentation, the resulting beer will also be clearer. Lager yeast(such as S-189, S-23, W-34 / 70) and many British yeast(such as US-04) have good sedimentation and flocculation.
Choose the right wine flower
In order to obtain the most intense aroma, some Brewers use the fragrant flowers of low alpha acid as boiled wine flowers instead of bitter flowers. In addition to the high cost of doing so, it will also introduce a large amount of polyphenols because of the addition of a large number of wine flowers, which will affect the clarity of the beer.
A large number of dry flowers(especially granules) can also cause some turbidity, and wine bags can be used to solve this problem.
Proper cleaning conditions
If the whole grain is brewed, the temperature must be controlled when washing(77-78 °C is the best), and the higher the washing temperature, the more polyphenols dissolved in the juice will also increase. When the washing temperature is higher than 82 °C, it will obviously affect the quality of the beer(polyphenols not only affect the clarity, but also cause astringent taste).
Excessive pH of washed water(greater than 8) also causes a large amount of polyphenols to enter the wort. Therefore, many refined Brewers will acidize the washing water to make its pH slightly lower than 6.0.
After the boiling is over, the sooner the juice is cooled from boiling to the fermentation temperature, the more Youliyudanning and the protein form a solidification deposit at the bottom of the cooking bucket. This can greatly reduce the protein and tannin turbidity suspended in the liquor. The ideal condition is: 20 liters of wort is cooled to room temperature within 15 minutes.
Use clarification agent
There are quite a few types of clarification agents available on the market. Here is a brief introduction to several commonly used products. The specific method of use is to follow the instructions provided by the supplier to operate the least error-prone.
L Irish Moss: Add 10-15 minutes before the end of cooking, and add 5 grams of Irish algae to 19 liters of Wort, which can effectively help proteins form cold coagulants when cooled, reducing the turbidity formed by proteins in beer.
L Whirlfluc Tablet: Very popular clarification agent in domestic brewing abroad, easy to operate. Similar to Irish algae, it is added 10 minutes before the end of cooking. One Whirlfluc Tablet is required for every 19 liters of wheat juice. Effective reduction of protein-induced turbidity
L GelatinG: Be sure to choose the colorless, odorless gelatin. The addition of 60-90 mg per liter of beer, added 4-5 days before the beer bottling, can effectively reduce the turbidity caused by protein and polyphenols.
L Isinglass: The collagen material extracted from fish bladders, mainly used in commercial brewing, has approximately twice the effect of gelatin. It can effectively solve the turbidity caused by yeast, and it can also reduce the turbidity caused by some proteins. When purchasing, you need to pay attention to the product description. This product has: pure fish glue, which needs to be mixed with organic acids before use; And the "convenient" type has been mixed with organic acids. The usage is 15-60 mg per liter of beer, added 4-5 days before the beer is bottled.
Filtering is a way to directly remove suspended particles from beer / ale. Yeast cells are generally 3-20 microns in diameter and are larger than proteins and polyphenols. Domestic brewing can be filtered with a filter of 5, 1, or 0.5 microns according to individual needs.
The filtration process before boiling can remove the hot solidification in the juice, and the filtration after cooling can remove the cold solidification. If it is also filtered before bottling, the remaining yeast in the liquor will be removed(two shots can not be bottled), and the wine will eventually need to be transferred into the Keg barrel for artificial carbonization.
Some documents also mention that filtration after fermentation will introduce additional oxygen into beer, causing oxidation problems; Taking carbon dioxide away from the filter can also lose some flavor in the beer. Therefore, if there is no professional filtering device, Gungun is not recommended to use filtering mesh after fermentation. It is also a good choice to add a clarifying agent before the fermentation is over.
Low temperature wine
Low temperatures are not conducive to yeast, proteins and tannins are suspended in the liquor, and low-temperature storage of beer(1-5 °C) can quickly clarify the beer.
Note: If bottling two operations are performed, it is necessary to wait until the bottle is completely over before cooling the beer. Otherwise, yeast can not completely decompose the two sugars and cause insufficient killing taste.