Converting All Grain Recipes to Extract
The majority of brewers (perhaps 70%) brew with malt extract recipes, though most serious enthusiasts have made the switch to all-grain. Yet it is the small percentage of expert brewers who write all of the brewing books and publish a large portion of recipes online. This can leave many extract brewers out in the cold.
The basic process for converting an all grain recipe to extract is as follows:
- Convert the base malt to an equivalent amount of extract
- Adjust the color of the beer down to match the original color
- Dial the hops up to match the IBUs of the original recipe
Converting a recipe is best done with the aid of brewing software or a good spreadsheet since you need to be able to adjust the original color, IBUs and original gravity estimates.
Converting Grains to Malt Extract
For the first step, convert your base malt to extract. The base malt is easy to identify as it is the largest ingredient in the beer – typically 5-10 lbs of pale malt. For example, let’s look at an all-grain ale with 8 lbs of pale malt and 1 lb of crystal malt. The simplest base malt conversion is to just multiply the number of pounds of pale male by 0.75 to get the pounds of liquid extract. Therefore 8 pounds of pale malt becomes 6 pounds of liquid extract. An equivalent conversion for dry extract is 0.6, so 8 pounds of pale malt becomes 4.8 pounds of dry malt.
To simplify things, we leave the specialty malts (1 lb of crystal) alone and switch to steeping them instead of mashing them. Some specialty malts (notably wheats, Munich malt, flaked and terrified grains) cannot be steeped and need to be replaced with a reasonable substitute.
A good rule of thumb is you should steep no more than 3-5 lbs of specialty grains in the final extract recipe. Obviously you want to choose your malt extract to match the original color and style of the beer. If you are converting a wheat beer, choose a wheat extract. Beers with large amounts of Munich malt require a Munich extract. If you are making a light colored beer, pick the palest extract you can find. Pale extract is always a good starting point.
Matching Beer Color
Once you have your base malt converted, the next step is to match your color. Malt extracts are almost always darker than the equivalent pale malt due to darkening in production and storage, so you will need to reduce the color and quantity your specialty malts to match the same color as the original beer.
If you don’t have home brewing software, the best way to come up with the same color as the original is really by trial and error. You can swap the existing specialty grains with lighter color grains (try 40L Crystal as a substitute for 60L Crystal malt for example), or you can reduce the amount of your darker colored specialty grains until you match the color of the original recipe.
Adjusting IBU Bitterness
The last step is to match the bitterness (IBUs) of the original beer. When going from all grain to extract this involves adding more hops because partial batch boils result in lower hop utilization than full batch boils used by all grain brewers. Some use a rule of thumb such as ‘add 20% more hops‘ but it is far more accurate to calculate and match the IBUs for both versions.
Again brewing software or spreadsheet is needed to calculate the International Bitterness Units (IBUs) of the original beer and final beer. Before starting, make sure you have the correct boil size both for the original beer and converted recipe set correctly when calculating IBUs.
All grain brewers use full size boils (6+ gallons for a 5 gallon brew), while extract brewers use much smaller boils (perhaps 2-3 gallons for 5 gallons of beer). This has a large effect on IBU calculation. Once you have both calculations set up, simply increase the hop additions incrementally until you reach your target bitterness.
You now have an extract recipe that will closely match your all grain recipe.
You can use the above three step guide with any brewing software or well designed spreadsheet to manually perform the three steps (convert base malt, adjust color, adjust bitterness).
If you wish to convert back (extract to all grain), you can follow the same three steps, but this time divide by the conversion factor (6 lbs of pale extract/0.75 = 8 lbs of pale malt).
Filed under: Brewing 101 on July 19th, 2009
