Sometimes when making a recipe it’s a lot easier to work backwards. Maybe you’ll think to yourself, “I would really like to make a beer that is 9% ABV”. Well to know how to answer this question you can use a formula to figure out how much DME or LME to use.
To calculate ABV:
(ABV/0.84) = approximate number of pounds of DME to use in a recipe
(ABV/0.71) = approximate number of pounds of LME to use in a recipe.
To show how this would work, lets say you want to make a 9.5% beer and you know you wanted to use dry malt extract. The formula would look like this:
(9.5/0.84) =approximate number of pounds of DME to use in a recipe
(9.5/0.84) = 11.4 lbs of dry malt extract.
The other formula that might be helpful is if you think in OG instead of ABV. When you are thinking in terms of original gravity the formula that you might want to use is this:
Using Extracts To Find Original Gravity:
(((Original Gravity – 1)(5))/0.044) = Approximate number of pounds of DME required to achieve correct original gravity
(((Original Gravity – 1)(5))/0.037) = Approximate number of pounds of LME required to achieve correct original gravity
An example of how to use this formula is, if you wanted to have a gravity of 1.056 but you didn’t know how much malt extract add you would use the formula above
(.28/0.044) = 6.36 lbs of dry malt extract to get a gravity of 1.056
This formula does not put into account the use of specialty grains. So I would not hold an absolute value on the number that you get at the end rather, I would use these formula’s for ballpark figures. If you are an all-grain brewer, we do have a conversion chart to help you out with that as well, hope it helps.