One of the biggest contributors in the brewing process – most beers are brewed using barley malt, but others also add wheat, rice and oats to the mix to create different colours, flavours and that all important mouthfeel. Some malts produce more fermentable sugars than others, and so will also influence the strength of your beer to a degree.
There's a reason why beer is sometimes known as "liquid bread", and that reason is down to the grains used to brew the beer with. They're also the reason why beer is so versatile and perfect with food.
Cereal grains are a rich source of energy, the seeds of plants where protein, starch and sugars are stored ready for the next sapling to start their journey.
No matter what grain is selected, it is taken through the same processes before it is fermented to produce alcohol:
Steeping and germination – the grain is steeped in warm water so that the germinated process starts. It is in this initial period that the majority of the protein in the grain is transformed into starch
Drying – once the malt has germinated, the brewer will want to halt that process before the seedlings start using all the starch they have just created. The grains are put in a hot kiln of up to 160°C and dried for 2-3 days. The majority of the grains left from this process will be used as the base malt in the beer
Roasting – A select amount of grain from the drying process will be further dried in the kilns at higher temperatures to achieve a different colour and convert the starch in the dried malt to produce different malt colour profiles and flavour. Short and low roasting will produce malts like Crystal malts (lightly kilned, with a sweet, caramalised flavour and a coppery tinge) to Chocolate malts (heavily roasted, and very bitter). These will impart the desired flavour characteristics of the brewer and are called the ‘speciality grains’
Once the grains have gone through this process, it is called malt. The choice of which is something that brewers spend a long time pouring over in order to achieve their desired beer.
Barley is most often used as it has a high concentration of “ears” on each stalk, and the hard outer husk, which made draining much easier. Barely is usually malted, but can be used unmalted to add a rich, dry character to the final beer. And there other grains that can be added to the base malt that can help define and shape the beer style:
Oats, like barley, can be malted or unmalted, and are added to the base malt to create a creamy and full-bodied beer for dark ales such as stout
Rye is used to create dry, sharp, whisky-like flavours and complexity. The grain can be used malted or unmalted, and brings a decent level of spiciness as well as dryess out a beer.
Wheat again, either malted or not, is a grain still highly packed with proteins and adds a full, smooth mouthfeel to the beer. The malt also creates a thick and heavy head, a tart flavour, and a desirable-looking haze
Corn/Maize is used in many beers (especially lagers) as it creates a light flavour, a clear body and a smooth flavour as it contains little protein and fermentable sugars
Rice has hardly any fermentable sugars and adds no discernable taste to the finished product but, like corn, is added to lighten the beer and allow for the delicate flavours of a light hopping to come through and is common in American and Japanese lagers. Whilst it doesn’t have a huge source of starch, it can contribute to a spritzy mouthfeel