Understanding Wort Yield in Beer Brewing: Unveiling the Secrets Behind Great Brews

Understanding Wort Yield in Beer Brewing: Unveiling the Secrets Behind Great Brews

I believe that many friends who have a certain understanding of beer brewing have heard of the term “wort yield”. First and foremost, let’s discuss the definition of wort yield: it represents the mass fraction of substances obtained from leaching every 100KG of wort after the raw materials have undergone saccharification. So, do you know what factors affect the wort yield?

The Impact of Grinding Degree

1. Controlling the grinding degree is a fundamental requirement for meeting particle size requirements. Grinding degree refers to the proportion of coarse and fine powders after crushing malt or adjuncts. It also includes the percentage of intact husks or the extent to which husks are broken. A reasonable grinding degree is reflected in good gelatinization and saccharification effects. It should ensure a short enzyme action time and a high leaching rate.

2. Proper control of grinding degree. For malt, the first priority is to avoid breaking the husk and try to keep it intact. In equipment filtered by a filter tank, the weight proportion of wheat husk plus residual particles on the husk (note that fewer residual particles attached to the husk is better) should be controlled at 35-45%. Poorly dissolved malt should not exceed 30%; fine powder content should be 15%-20% for well-dissolved malt and 25%-30% for poorly dissolved malt.

ACE 500L Beer Brewery Equipment

The Influence of Material-Water Ratio

1. Material-water ratio refers to the ratio of input material volume to water volume, also known as saccharification water consumption. It is an important technical parameter in saccharification process design and is generally based on extract concentration and first wort.

2. Different material-water ratios affect the stability of various enzymes, including enzyme-substrate contact and substrate-product dispersion. A relatively small material-water ratio, i.e., thicker mash, may enhance enzyme heat resistance and stability, but it will also impact enzyme-substrate dispersion and function. A larger material-water ratio, i.e., lower mash viscosity, is beneficial for enzyme dispersion, substrate-product dispersion, and leaching of malt and adjuncts extractables, resulting in better gelatinization and saccharification effects. However, it should be noted that enzyme heat resistance and stability are relatively poor in this case, and the proportion of inactivation increases with temperature. Moreover, if the total material-water ratio is too large or too small, i.e., the mash concentration is either too high or too low, it will affect the extract yield during the sparging process. A thicker mash will result in higher residual sugar in the grains, while a thinner mash reduces the difference between the concentration of saccharified wort and mixed wort, as well as the amount of water used for sparging, affecting the extract yield.

The Influence of Saccharification Process

An appropriate saccharification process provides optimal conditions for various enzymes to function effectively, resulting in improved saccharification yield.

1. Saccharification temperature: Different enzymes have their respective optimal action and inactivation temperatures during saccharification. To prevent enzyme denaturation caused by high temperature, the saccharification temperature gradually increases from low to high. This temperature change is divided into several stages, each creating optimal conditions for enzyme activity.

2. pH value: Malt enzymes have specific pH optima. Controlling the pH value promotes saccharification by facilitating faster and more complete amylase breakdown of starch, leading to a higher wort yield.

The Impact of Sparging Operation

1. Grain sparging water temperature: Generally controlled between 76-78 degrees Celsius, if the water temperature is too low (lower than the temperature of grains in the filter tank), it causes grain bed compaction, increasing filtration resistance and resulting in incomplete removal of residual sugar, thus reducing wort yield. Conversely, if the water temperature exceeds 80 degrees Celsius, it adversely affects wort quality.

2. Number and amount of sparges: Typically, sparging is done 3-4 times. The first sparge employs the largest amount of water, accounting for approximately 50% of the total volume. The second and third sparges depend on decreases in concentration of the underlayer. The final wort sparging involves the least amount of water and is known as regulated wort sparging. It adjusts the final wort concentration based on boiling time and evaporation intensity. Therefore, the remaining wort water should be utilized to the maximum extent, as high residual sugar will lead to a lower wort yield.

3. Grains and top-water action: Grain movement during sparging is necessary as it not only loosens the compacted layer but also allows washing water to evenly flow through all layers to enhance cleaning. In cases of difficult filtration, top-watering is often used to reorganize the grain bed. Although top-watering can dilute unfiltered wort by introducing a significant amount of water into the grain bed, it does not distribute uniformly like sparging water does. Consequently, top-watering dilutes the wort layer and unfiltered wort to a certain extent, but not as effectively as sparging, which affects the number of possible sparges and water consumption while potentially increasing residual sugar content. Therefore, it is advisable to avoid top-watering during the initial wort filtration and instead adjust the wort flow rate based on experience and filtration conditions. However, for the first grain sparge, top-watering is recommended as the wheat grain bed has already compacted, and top-watering helps loosen this layer, facilitating subsequent sparging while preventing excessive residual sugar. Note that there should be a certain period of reflux after top-watering so that water not fully mixed with the underlayer can return to the upper part of the grain bed, ensuring effective washing.

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