Better Beer with Late Malt Extract Additions

by Brad Smith on February 20, 2008 · 21 comments

malt extract

Today we look at a method for malt extract brewers that can improve the quality and color of your extract beer. Both liquid and dried malt extract beers suffer from an effect called a Maillard reaction as well as carmelization when brewing. A Maillard reaction is a chemical reaction that occurs between amino acids and sugars in the wort, and it accentuated by the use of extract in a concentrated boil. Carmelization occurs when liquid extract or excess sugars settle to the bottom of the brew pot during the boil and the sugars carmelize (harden) in the bottom of the pot. Of the two, the Maillard reaction actually accounts for the majority of the color darkening.

This typically darkens the beer, and in extreme cases can also affect the taste of the beer. Obviously this is a problem for brewers of light colored beers. The effect is also common in high gravity beers in small brew pots because of the higher proportion of extract to water when boiling.

To avoid the ill effects of the Maillard reaction and carmelization, malt extract brewers should delay the addition of the majority of their extracts until late in the boiling process. The extract must be added late enough in the boil to avoid darkening, but early enough to assure that the extract is sterilized. Boiling the extract for about 15 minutes is a good balance.

I recommend adding a small amount of malt extract (perhaps 15-25%) early in the boil if using separate hops. The sugars and enzymes in the extract aid in extracting alpha acids (bitterness) from the hops. Boiling hops with a small amount of extract will result in smoother hop flavors and appropriate bitterness that you can’t achieve with plain water alone.

Late extract additions do present one challenge for the brewer. Late extract additions increase the bitterness of the beer. Predicting the International Bitterness Units (IBUs) of late extract additions to match your target style is mathematically complex. Most brewing software and spreadsheets are simply not designed to handle multiple hop and late malt extract additions in the boil. The gravity and bitterness of the boil will vary with each ingredient added.

To do the calculation by hand you would need to calculate the gravity of the boil at each stage, bitterness contribution from each hop addition taking this gravity into account and then combine these into one overall IBU number for the brew. To compensate, some brewers use a “rule of thumb” such as “reduce hops by 20% when using late extract brews”. Another method is to calculate the hops addition without the late extract and then add 5-10% more hops to compensate for lower utilization during the last 15 minutes of the boil.

Recently we did add a late extract option to BeerSmith. To use the late extract option, simply check the “late extract” box when adding extracts to your recipe and specify the boil time. BeerSmith will include all of your hop additions and late extract additions into the IBU (bitterness) calculations, combining them appropriately to predict your overall bitterness (IBUs).

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