Extract is malted barley that has had its starches converted into sugars, then separated from residual grain pieces, and boiled at a very low temperature in a vacuum to reduce it down into a thick syrup. Brewers then dilute the extract syrup in water, and being their brewing session.
Some brewers prefer extracts, as they save time, are extremely consistent, and make very high quality beers. Other brewers may employ all-grain brewing, in which wort is made from malted barley grains. The process requires manually converting starches into sugars using enzymes in the malt, and is mostly used by more advanced brewers, or those with a very specific purpose in mind. In terms of quality, if care is taken in all brewing steps, one will not taste a difference between an extract beer and an all-grain beer. The decision between all-grain versus extract brewing should come down to personal preference, not a perceived quality difference.
Dry and Liquid Extracts
There are two forms that malt extract takes: dry and liquid. Both are made in the same way, except dry malt extract is further processed to render it into a powder. Dry malt extracts (or DME) have a slightly higher sugar content by weight versus liquid, and has a much longer shelf life. Liquid malt extracts (or LME) has slightly less sugar content per pound, has a shorter shelf life, but is generally seen as being easier to use. DME is extremely hydrophilic, meaning any moisture it encounters will be immediately absorbed, causing it to clump up. DME requires a lot of agitation to break apart clumps and dissolve completely in water. Liquid extract requires some stirring to dissolve. The decision on which type of extract to use generally comes down to personal preference.
Because the only functional difference between DME and LME is water content, sugar content will, as a side effect, be different between the two. Roughly speaking, in terms of sugar content, 1 pound of DME equates to 1.2 pounds of LME, which equates to 1.5 pounds of malted barley.
Light, Amber, and Dark Extracts
Malt extracts types available are referred to by a color: pale, golden light, amber, or dark typically. The difference between the types is the specific malt blends used to create them. Amber and dark malts will have crystal malts and other darker malts in various proportions to reach the specific flavor profile. Because these two have a specified blend of malts they are made with, it is best not to add additional malts on top of them, as this will likely lead to a very thick, cloying beer that. Most extract brewers prefer to find the lightest extracts available, and customize their own specific specialty malt blend on top of them. This is general seen as the best practice, as you are not relying on what the manufacturer produces for you. Most extract produces will list the specific malt blends that make up their extracts, though this may not always be the case.
Brewing with Extracts
There are three methods of brewing with extract, differentiated based on the use and method of use of specialty grains. First is all extract, in which no additional steeping grains are used. Here, extract is dissolved in water to make the wort.
Second is extract with steeping grains. Specialty malts are steeped in hot water to extract color and flavor compounds. This is the most common extract-brewing method, as it allows an easy brew with a lot of different options, with regards to specific beer styles. Steeping grains is very straight-forward, usually grains are put in a large bag and steeped, very similar to tea.
The final method is partial mash brewing. Here, a small mash is performed, wherein starches are converted to fermentable sugars, then extract is used to supplant sugars to raise sugar content up to a specific level. This method is the most adaptable, as it allows the brewer to play around with any malt or beer profile they’d like. The specific proportion of extract-to-grains is up to the brewer, and usually comes down to the brewer’s available equipment. All-grain brewers may even find themselves partial mashing, if for example their mash goes awry and need additional sugars to balance out the final beer.
As with many aspects of homebrewing, the decision of which mode of extract brewing should come down to personal preference and style of beer being brewed.