Extract Conversion Calculator

Swapping one fermentable form for another, liquid malt extract (LME), dry malt extract (DME), or base grain, only works cleanly when the swap preserves the same gravity contribution. Two conversion modes cover the two situations that come up in practice: a straight LME-to-DME swap based on their fixed gravity ratio, and a general conversion between any combination of LME, DME, and base grain that accounts for differences in extract potential (PPG) and brewhouse efficiency.

The LME-to-DME conversion is DME = LME x (37 / 45), reflecting that DME has a higher points-per-pound-per-gallon value than LME. The reverse conversion is LME = DME x (45 / 37). The general extract-to-grain conversion is Final Amount = (Beginning Amount x Beginning PPG x Beginning Efficiency) / (Final PPG x Final Efficiency). This accounts for the fact that base grains need mashing at a brewhouse efficiency below 100%, while extracts are assumed to deliver their full rated PPG.

Default PPG values are 37 for LME, 45 for DME, and 35 for base grain, adjustable when a specific malt extract or grain differs from those defaults. Brewhouse efficiency applies only to grain conversions; extract types default to 100% efficiency since nothing is lost to incomplete conversion or lautering.

Converting 6 pounds of LME to DME: 6 x (37 / 45) = 6 x 0.8222, or about 4.93 pounds of DME, at the same gravity contribution. Converting that same recipe further, from 5 pounds of LME (PPG 37, 100% efficiency) to base grain (PPG 35) mashed at 75% efficiency: Final Amount = (5 x 37 x 100) / (35 x 75) = 18,500 / 2,625, or about 7.05 pounds of grain, the extra weight accounting for the sugar the mash itself will not fully convert.

Brewers frequently need to substitute one fermentable form for another when adapting recipes, adjusting inventory, or transitioning between brewing methods, and the gravity math behind the swap keeps an original gravity target consistent.

• Extract Recipe Adaptation: A recipe calling for 6 lb of LME converts to its DME equivalent when a homebrew shop only stocks dry extract.
• All-Grain Transition: Moving from extract brewing to all-grain converts LME and DME amounts to base grain weights, accounting for a specific brewhouse efficiency to keep the same gravity contribution.
• Partial Mash Recipes: Determining how much base grain substitutes for a portion of extract in a partial mash recipe converts only the amount being replaced while the rest stays as extract.
• Inventory Management: Leftover DME on hand when a recipe calls for LME converts to the correct substitution weight without manual calculation.
• Recipe Scaling: After scaling a recipe up or down, checking the new amounts against the target gravity verifies the extract-to-grain conversions still hold.
• Efficiency Comparison: Comparing grain requirements across brewhouse efficiency levels from 65% to 80% shows how much a system's efficiency affects grain quantities.
• Competition Brewing: Converting a proven extract recipe to all-grain format for competition entry, using exact PPG values from a malt supplier's specification sheet, keeps precise gravity matching.
• Education: The relationship between extract potential, brewhouse efficiency, and fermentable weight becomes visible in the step-by-step view, which shows how each variable affects the final amount.