Subbing DME for LME

Both DME and LME are great options for homebrewers looking to brew without the hassle of mashing. In general, DME has a longer shelf life than LME because of its lower water content; about 5% compared to about 25%. When LME ages, especially when stored at room or elevated temperatures, a range of unpleasant compounds develop that include molasses-, licorice-, and cardboard-like flavors. Collectively, these off-flavors impart a distinctive “twang” to LME. Before homebrewers generally understood the relationship between aged LME and beer flavor, homebrewed beers were often characterized by this strange “homebrew twang” that is absent in commercially brewed beers, except for the rarest of the rare examples brewed using old LME; uncommon in commercial beers because few use LME and those that do tend to use it shortly after purchasing.

The short answer to your question is no; subbing DME for LME does not have any negative effects to your finished beer. And doing so for the reason you stated makes perfect sense. Indeed, one way to improve the flavor of beer brewed from extracts is by using DME instead of LME. It’s important to note that LME, in and of itself, does not cause off-flavors; it’s just a problem when it is old and twangy.

It’s also important to account for the differences in moisture when subbing DME for LME. For example, 1 pound/kilo of DME at 5% moisture is equal to 1.27 pounds/kilos LME at 25% moisture (calculated by dividing 95% solids by 75% solids). The challenge with this conversion is we do not always know the moisture content of the ingredients we are using at home. The good news is that most raw material suppliers producing products intended for the homebrewing market make their product specification sheets relatively easy to find, and moisture content is one piece of information found on specification sheets for DME and LME.