Beer Brewing Wort Boiling Tips

During the brewing process, wort boiling is a complex physical and chemical change. These changes are intricate and complex, and it is difficult to take into account the favorable conditions of all changes at the same time. To a large extent, they need to be mastered according to the type of product and operating experience.Now, let's learn about the little knowledge about wort boiling.

First of all, do you know why wort is boiled?

Stable wort ingredients

01 Enzyme inactivation

Destroy the malt enzyme activity and make it lose its effect. It is mainly to stop the action of amylase and stabilize the ratio of fermentable sugar and dextrin in wort to maintain consistency of wort components and fermentation.

02 Wort sterilization

Through boiling, all kinds of fungi, especially lactic acid bacteria, are eliminated in the wort, and the spoilage during fermentation is avoided to ensure the quality of the final product.

03 Protein denaturation and flocculation.

During the boiling process, some proteins that are thermally denatured and combined with tannin substances are flocculated to precipitate the proteins, in order to improve the abiotic stability of beer.

04 Evaporated water

Evaporate the excess water in the wort to concentrate the wort to the required concentration.

05 Extraction of hop ingredients

Add hops during the wort boiling process to dissolve the soft resins, tannins and aromatic components contained in it to give the wort a unique bitterness and aroma, while also improving the biological and abiotic stability of the beer.

But besides that, wort boiling brings some other reactions.

01 Lowering the wort pH

When the wort is boiled, the pH value of the wort is further reduced due to the addition of hops, the formation of acidic melanoids, and the acidification of calcium and magnesium ions in the water, which promotes the precipitation of B-globulin and the finished product The decrease of beer pH value is beneficial to the biological stability and abiotic stability of beer.

02 Formation of reducing substances

During the boiling process, the wort color gradually deepens, and some reducing substances with complex components, such as reduced ketones, are formed, which enhances the antioxidant capacity of the wort.These substances are very effective in maintaining beer flavor stability and abiotic stability.

03 Steam out bad volatile components

During the boiling process, some of the original and newly formed volatility volatile components in the wort are distilled out, including some of the badly flavored hydrocarbon components in hop oil, such as geranene.

So what should we do

How to perfect the technical conditions of wort boiling?

01 Wort boiling time

To determine the wort boiling time, the wort concentration should be mastered according to the wort boiling intensity, so as to achieve the final wort concentration required within the prescribed boiling time.

The wort boiling time has a great effect on the properties of beer.When boiling at normal pressure, the boiling time of light beer (10% ~ 12%) is generally controlled at 1.5 ~ 2h, and thick beer can be appropriately extended; under pressure of 0.11 ~ 012MPa Boil under the conditions, the time can be shortened by about half.

Reasonably prolonging the boiling time is beneficial for protein coagulation, hop utilization and the formation of reducing substances, but it is not good for foam performance.

Excessively extending the boiling time is not only economically unreasonable, but the wort quality will also decrease. For example: dark wort, rough taste, reduced bitterness, poor foam, etc., for light beer, the impact is more serious.

02 Wort boiling strength

When the wort is boiled, the water evaporated per hour is equivalent to the percentage of the wort mixed, which is the boiling strength. The boiling strength is closely related to the thermal conductivity, shape, heating area, steam pressure, evaporation area of wort, and boiling method of the boiling pot. Under the same boiling time and pH value, the boiling strength is the determinant of the protein coagulation. Different boiling strengths have different transparency of wort, and the amount of solidifying nitrogen contained in them is also significantly different, but too high boiling strength is not very beneficial.

03 PH

PH is closely related to protein coagulation, wort color and flavor.

The protein in wort is the most unstable at its isoelectric point and is easy to coagulate and precipitate. The isoelectric points of various proteins in wort are different. Therefore, at different pH values, the precipitation also occurs first. The ideal pH value for wort boiling is 5.2, but this value is difficult to achieve under normal conditions, and it is more difficult to achieve it with hard water saccharification. Generally, when acidification is started or wort is boiled, acidification is used to make Its pH decreases. When the pH value is in the range of 5.2 ~ 5.6, the protein can generally reach a good degree of coagulation. The better the protein coagulation, the better the abiotic stability of the beer.

The interaction between polyphenols and proteins is also an important aspect that promotes protein coagulation and precipitation. The lower the pH value of boiled wort, the easier it is for polyphenols such as tannins and anthocyanins to interact with proteins to precipitate out, which reduces wort color, improves beer taste, and improves abiotic stability of beer.

Although lower pH value is beneficial for protein coagulation, it is not beneficial for hop isomerization of α-acid, which reduces the utilization rate of hops.

It is ideal to grasp the pH value of the wort when it is in the range of 5.2 ~ 5.4.