Erik Drews

SOSComAlt

Week 8 Beer update

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This week at cascadia homebrew we made a cardamom coffee stout while discussing malts and water chemistry further in depth.

Vocabulary Words:

• Alpha amylase- one of the main diastatic enzymes at play in the brewing process responsible for converting starches into more complex fermentable sugars.
• Beta amylase-one of the main diastatic enzymes at play in the brewing process responsible for converting starches into simpler fermentable sugars.
• Polysaccharides- a carbohydrate (starch, glycogen or cellulose) whose molecules consist of a number of sugar molecules bonded together.
• Imperial-an imperial beer typically refers to stronger flavors and higher alcohol content than the generic form of said beer. Ex, an imperial stout will be higher in alcohol and more robust in flavor than a regular stout.

Alpha amylase will break down long chain starch polysaccharides into large chunks of fermentable sugars. These sugars are digestible for yeast but yeast will digest them slowly with more difficulty resulting in a maltier beer with less alcohol and residual sweetness. Beers that use primarily alpha amylase will have a higher final gravity, which will translate to a lower specific gravity.

Beta amylase will break down long chain starch polysaccharides into small chucks of fermentable sugars that are very easily digestible for yeast cells resulting in a less malty beer that has a dry body with less sweetness that is higher in alcohol. Beers that use primarily beta amylase will have a lower final gravity, which will translate to a higher specific gravity.

Both alpha and beta amylase are present in malted barley and work most efficiently at a ph of 5.2. However alpha amylase works more efficiently at the higher end of the mash temperature spectrum (148°F-158°F) while beta amylase works more efficiently at the low end of the mash temperature spectrum. At the high end of this spectrum alpha amylase will be the dominant diastatic enzyme at work while beta amylase will be barely working or not at all. At the low end of this spectrum the opposite is true, beta amylase will be the dominant diastatic enzyme at work while alpha amylase will be barely working or not at all. The two optimum ranges overlap within the middle of this spectrum. If a the grains are mashed at 153°F,(medium spectrum) one can assume that half of the fermentable sugars will be simple and half will be complex resulting in a finished beer that is halfway between malty and dry.

This rule is helpful but it must be taken into account that if a malt is heavily roasted, its starches will be so damaged that they will be converted into complex sugars regardless of the type of enzyme that is employed. For example grain bill of 100% Pilsen malts mashed at 148°F may have an extremely low final gravity such as 1.002, whereas a darker grain bill mashed at the same 148°F may end up with a final gravity of around 1.018 which is rather high. This is because of those damaged starch polysaccharides that result from the heat damage caused by heavy roasting.

Hops: typical flavor profiles of hops by location.

American style hops: Citrus, piney flavors

German style hops: Earthy, spicy, slightly floral

English style hops: Floral, earthy, subtle fruitiness

Australia/New Zealand style hops: Fruity

Carboy being filled with stout wort prior to oxygenation and fermentation

Water Chemistry basics:

Chemicals that are added to the water in the brewing process have a number of functions. Among the most common are ph and mineral adjustments. Flavor is also greatly impacted by the ratio of sulfates to chlorides. Sulfates are added via gypsum addition and chlorides are added via calcium chloride additions. A Maltier beer will have a higher chloride to sulfate ratio such as .7 Sulfates to 1 chloride while a more bitter beer will have a higher sulfate to chloride ratio such as 1.4 sulfates to 1 chloride.

Calcium Carbonate is added to increase the hardness or mineral content of the water, this addition will also inadvertently raise the water’s alkalinity. When calcium chloride is added, acidulated malts may be used to lower the ph down to the optimum range of 5.2, this way hardness can be achieved without sacrificing enzymatic efficiency.