AleArchive | Calculators | Convert Fermentables

Fermentable Source Converter

This calculator can be used to help with substituting one fermentable source for another. Inputs and outputs can be in the form of liquid malt extract (LME), dry malt extract (DME) or grain.


Input Fermentable:

Output Fermentable:

Weight Units (optional)


About this Calculator

This calculator can be used to determine how much of one fermentable source needs to be substituted for another source in order to achieve the same (or very similar) wort gravity. For example, this calculator can be useful in situations where a recipe calls for the use of liquid malt extract (LME), but you only have dry malt extract (DME) on hand. Because LME, DME, and grain all contribute different amounts of fermentable sugar to the wort per unit weight, one cannot simply add the same weight and get the same result.

Fortunately converting between two sources is straightforward, once you know how much fermentable sugar each source adds per unit weight. To determine the new weight, you can just multiply the original weight by the ratio of the fermentable sugar contribution of each source, as shown in the following formula:

Output_Weight = Input_Weight * (Input_ppg / Output_ppg)

In this formula, Input_ppg and Output_ppg represent the points per pound per gallon of fermentable sugar each source adds to the wort.

Key Assumptions

To perform the calculation, this calculator makes the following assumptions about gravity contributions for each type of fermentable:

Note: The 27 PPG assumed for grain corresponds to an extract efficiency of about 75%. If your extract efficiency is significantly different than this, calcualtions involving grain may not be accurate for your system.