Adjuncts

This page is in progress
Please check back later for additional changes

Adjuncts are unmalted cereals and sugars that are used as a replacement (usually in part) for malted barley (or other malted cereals such as wheat, sorghum, oats, etc.).

Barley malt is a relatively expensive ingredient in the brewing process as it is the product of controlled barley germination and kilning (heat drying) that typically takes 6-8 days and consumes substantial amounts of energy and water. As such, many conventional brewing styles (eg Asia and Nth America) use unmalted starch adjuncts such as barley, wheat, maize or rice that are added to the mash at levels up to up to 60% or even >75% (of malt charge) for the Happoshu style in Japan (Brandee et al., 1999; Haywood, 1996). These are added not only as a cheap source of extract, but also give brewers control over attenuation, mouth-feel, flavor, foam head retention or are the result of constraints in local availability.

In brewing, an adjunct is a source of extract other than malt. The term most often refers to unmalted cereal grain, such as rice, which can be used in the mash. The enzyme potential of the malt is usually sufficient to break down this additional starch during mashing. Adjunct grain is generally less expensive than malt, and therefore it's used as part of the grist in 85-90% of beer produced worldwide. However, since the price and availability of malt is typically not a concern for home brewers, the main reason to use unmalted grains is for their special coloring and flavoring characteristics for the creation of innovative beer types. Sometimes adjunct may also be used to describe non-grain sources of fermentable sugars, such as fruit or honey.

Adjuncts will usually be used as less-expensive sources of fermentable extract. In addition, adjuncts can be used to impart elements of beer characteristics and quality such as color, flavor, foam, body, and drinkability.

The term "adjuncts" does not include materials that are peripheral to beer and do not become part of the final malt beverage product such as filter aids, insoluble colloidal stabilization agents, brewing water treatment materials, consumed yeast nutrients, yeast wash and care materials, and coagulant and flocculents that settle and are filtered out.

There is a limit to the amount of adjunct that can be used to make a wort that will provide enough nutrients for the yeast to produce an acceptable beer and where the yeast remains vital and viable enough to be used again. The limit (for most brewing yeast strains) is around 50% adjunct. At this point, the amount of nitrogenous material, commonly measured as free amino nitrogen, becomes so low that yeast nitrogen is significantly modified,6 leading to flavor changes in the beer.

When brewing with adjuncts, keep in mind:

• Adjuncts generally do not provide adequate nutrition for the yeast. Therefore nutrient supplementation is typically beneficial to ensure a healthy fermentation.
• Adjuncts do not provide enzymes to aid starch conversion. Therefore adjucts can only constitute up to about 50% of the grist without requiring the addition of exogenous enzymes, depending on the base malt. However 15-20% is generally a safer limit.
• Starchy adjuncts must either be pre-gelatinized, or have a gelatinization temperature lower than the beta-amylase rest. See Mashing.
• Difficulty recirculating or lautering may be caused by using huskless adjuncts in the mash.
• Adjuncts often contain relatively more glucose than malt. Yeast fermentation of maltose is repressed by glucose, therefore fermentation patterns of all malt all-malt/adjunct mixtures might differ from each other.

Torrification of cereals is a process by which cereal grains are subjected to heat at 260ºC and expanded or "popped" (popcorn process). This process renders the starch pregelatinized and thereby eliminates the brewhouse cooking step. There are no handling or dust problems associated with the use of torrified cereals. It is possible to blend these torrified products with malt. They can then be ground simultaneously and mashed-in together. However, if they are used and the torrified product is cooked at 71ºC to 77ºC prior to addition to malt, higher yields will result. Torrified cereals lead to increased lauter grain bed depth and to slight runoff penalties. Particle size and mill settings are critical, with large particle size leading to poor yield and with too fine a grind resulting in runoff problems.

Maize, rice, and sorghum are also available as grits. Grits are small chunks of unprocessed endosperm. Rice grits are generally the by-product of processing of rice for food (the broken bits). Grits need to be cooked to gelatinize their starch granules before being added to a mash. Enzymes are also helpful to start the starch conversion in the cereal cooker or aid it in the mashing vessel. Grits have the same flavor/color properties as their torrefied counterparts (not much).

The beers produced with grain adjuncts contain less nitrogen, they show a lower final degree of fermentation, better foaming properties, but poorer filterability. The taste stability can leave something to be desired compared to pure malt beers.

For grain adjuncts, see Grain.
For sugar adjuncts, see Sugars.

---

Fun fact: The Reinheitsgebot "Purity Law" restricts the use of adjuncts in German beer.