This is the Brew and Build glossary. It is a library where you can find information on terms used throughout the website and in brewing. I will slowly update this glossary as I get time.
Adjunct – these are unmalted grains or grain products used in brewing beer which supplement the main ingredients of the mash. This is often done to reduce costs, but sometimes also to create an additional benefits, such as better foam retention or flavours. Both solid and liquid adjuncts are commonly used.
Decoction – Decoction mashing is a reference to removing part or all of the grains from the main body of the mash. In a ‘true’ decoction, the grains are heated to a higher temperature than the main mash, and brought into the alpha amylase conversion range. This allows the long chain starch molecules to be converted into long chain sugars. This is then generally brought to a boil. When the decocted section is reincorporated with the main body, these long chain sugars are then easily broken into shorter chain sugars by the beta amylase enzymes. This was a popular method of starch conversion when malting techniques were less efficient and less consistent. The other benefits include caramalisation of the sugars and extraction of tannins. For more details have a look here.
DME – Dried Malt Extract. This is a dried malt powder, produced by malt manufacturers by mashing malted grains in water exactly the same way as all grain brewers produce their wort. It has been mashed with all the correct minerals and ph to produce the malt sugars required for brewing. It is then dried into a powder. Because the extract already has the salts and minerals, no further water adjustment should be required for extract brewers. For more details have a look here.
Diastatic Power – This refers to the enzymatic power of the malt grains. The malts ability to break down it’s own starches (and other adjuncts in the mash) into simpler fermentable sugars during the mashing process. As an example, 2-Row base malt has a lower diastatic power than 6-Row base malt. Diastatic power of a grain is measured in Lintner.
Iodine Test – An iodine test is done at the end of the mash, to check whether the starches from the grains have been converted to fermentable sugars by the enzymes. If the test is clear and no starches are present, then the iodine remains yellow. If there is starch present, the iodine will turn purple/ brown. At this point, the brewer will probably extend the mash time to get full conversion.
Melanoidins – are brown polymers that are formed when sugars and amino acids combine (through the Maillard Reaction) at high temperatures. Melanoidins tend to be found in foods that have undergone some form of browning, such as malted barley, bread crust, bakery products and coffee. See here for more.
Maillard Reaction – is the chemical reaction between a reducing sugar and an amino acid, usually requiring heat. The maillard reaction produces Melanoidins which give dark roasted foods many of their delicious flavours and aromas. See here for more.
Mash Hopping – This is quite an old technique of putting hops into the mash, that has been getting more attention recently. The benefits are touted as a smoother bitterness than early boil hops, and also extraction of Thiol precursors, which contribute to more fruit forward flavours being produced during fermentation. This is largely attributed to the bio-transformation that occurs with the thiols and the yeast. Much of the common understanding of mash hopping has come from the work of Scott Janish. See here for more.
Reinheitsgebot – German beer purity law, stating that all beer must be made of only 4 ingredients – Malted grains, Hops, Yeast and Water. This law was originally introduced to stop beer brewers competing for grains such as wheat and rye, which would have raised prices for baked goods. Later it was an instrument to combat the introduction of cheaper ingredients such as corn or rice, which were being used to flesh out beer in places like the US. See here for more.
Wort – A sweet liquid which is derived from extraction of the sugars produced when mashing malted grains. See here for more.