Malt extract is a concentrated form of wort similar to that which is contained in a beer kit. However, unlike a beer kit where the extract is hopped, the contents in a standard can of extract are unhopped which means it will not have the bitterness, taste or aromas associated with hops. Malt extracts generally come in two forms. Dry malt extract (DME) which is also known as spray malt, and liquid malt extract (LME). Dry malt extract is sold in the form of a powder and liquid malt extract is sold in the form of a syrup.
Below is an example of some cans of LME from the Coopers range of products:
It is assumed that LME is of a slightly higher quality than DME and is prefferable when home brewing. This is due to the processes used to make DME. However in order to notice this difference you must ensure that your LME is fresh and has been stored correctly in a cool place. LME is also more expensive than DME and once that tin is open it must be used quickly. DME can be kept for years if it has been stored correctly.
Below is an example of DME from Muntons and Brupaks ranges:
Malt extracts are used in brewing for various things. For instance when brewing with a 1kg kit, malt extract can be used as a replacement for sugar giving your beer a lot more body and flavour, it can also be used as a replacement for sugar when priming. However, its not really worth priming with malt as the amount of sugar used is so small it will not be noticeable and malt is a lot more expensive than sugar. A lot of home brewers use malt extracts to create a beer of their own without having to go through the long mashing process associated with AG brewing. More on this later in our technique section.
There are various kinds of malt extracts available such as light, medium, dark, and wheat. They are all used for different beer styles. For example, lighter malts can be used for English style real ales where as dark malts could be used for stouts or winter beers. How you use them is entirely up to you. Half the fun of home brewing is experimenting. Sometimes it works, sometimes it doesnt. Sometimes you make a mistake and it tastes terrible, sometimes you make a mistake and it tastes great.