Brew Log

Batch Performance

Will show a summary of your brew session.


There are four main types of efficiency in the brewing world.

More details about the Brewing Efficiency Chart Efficiency calculations only apply to All Grain, BIAB, and Partial Mash recipes. Each type references a different point in the brewing process. The system uses Brew Log entries to compute each of them: 1) Conversion Efficiency: The percentage of total available sugars that were extracted from the grains inside the mash tun.

  • Brew Log Type - 'Mash Complete'.

  • Measurement Option A - first runnings:

    • Gravity - sample taken from first runnings.

    • Volume - strike water used (count all water added to the MLT before the sample was taken).

    • Generally, only accurate for recirculated mash systems.

  • Measurement Option B - blend of runnings:

    • Gravity - sample taken before the boil, blend of all runnings.

    • Volume - how much water went into the MLT, counting strike and sparge water.

    • Note: With Option B, the wort sample must be fully blended from all the runnings to be accurate. First runnings have a higher gravity than second runnings.

    • Best option for batch sparges. Works for BIAB and partial mash (MLT and kettle are the same).

  • The equation the system uses comes from Braukaiser's article on Understanding Efficiency. We believe this is the most accurate equation out there because of the 3rd term which accounts for the volume increase from the extracted sugars.

2) Pre-Boil Efficiency: The percentage of total available sugars that made it into the kettle.

  • Brew Log Type - 'Pre-Boil Gravity'.

  • Gravity - measured before the boil, blend of all runnings.

  • Volume - how much wort went into the kettle.

  • Volume losses from mash tun dead space and grain absorption count against this measure.

3) Ending Kettle Efficiency: The percentage of total sugars in the kettle after the boil. Theoretically the same as Pre-Boil Efficiency, provided accurate measurements at both points (minus rounding error).

  • Brew Log Type - 'Boil Complete'.

  • Gravity - OG, measured after cooling, before pitching yeast.

  • Volume - ending kettle volume when cooled, before draining.

  • Kettle dead space, trub losses, and hops absorption do NOT count against this measure.

  • There is a corner case in all grain brewing, where an 'all grain' recipe includes raw sugar or extract. In this situation, the extract / sugar additions are expected to be in the wort at this point, thus increasing the gravity reading. The system excludes the gravity contribution from the sugar for the purposes of this calculation. This is not a typical situation in all grain brewing, but if you are adding some sugar to your IIPA, then you can still get solid numbers.

Ending Kettle Efficiency is the efficiency factor used on the recipe editor when batch size target is set to 'Kettle'. 4) Brew House Efficiency: An all inclusive measure of efficiency, which counts all losses to the fermentor. This can be thought of as 'to the fermentor' efficiency.

  • Brew Log Type - 'Brew Day Complete'.

  • Gravity - OG, measured after cooling, and before pitching yeast.

  • Volume - how much wort made it into the fermentor.

  • All losses that do not make it into the fermentor are counted against this measure, including hops absorption (which varies by recipe), and trub losses.

Brew House Efficiency is the efficiency factor used on the recipe editor when batch size target is set to 'Fermentor'. Additional Information: Partial Mash Recipes - Pre-Boil Efficiency is not reported. This is because partial mash is a simplified brewing method that always includes extract or sugar. The numbers do not always match up perfectly (even if you hit exactly what the recipe says), because the recipe editor uses non-rounded values for computations. See the ABV FAQ for more info about that.

Alcohol and Attenuation

How does the brew session report ABV, and why doesn't it always match the recipe exactly even though I hit the same values?The system will calculate the actual ABV of your finished beer using gravity readings entered in the brew log. The ABV equation selected on the recipe is used to calculate the actual ABV. Read more about the equations here. The numbers do not always match up perfectly (even if you hit exactly what the recipe says), because the recipe editor uses non-rounded values for computations. Even though the OG on the recipe reads 1.050, behind the scenes it could be something like 1.0504386. In some cases, this is enough to cause minor differences. You can experiment with this yourself by entering a gravity reading of 1.0504 in the brew log, and see the impact it has. The value will be rounded to 3 places in the log listing, but the detail is retained in the system. We feel it is better to avoid rounding until the end inside the software, and live with the limitations of hydrometer scale resolution when calculating actual ABV. For ABV and attenuation to be reported, enter a 'Brew Day Complete' log, and a 'Fermentation Complete' log. By entering 'Sample', or 'Racked' log entries, the system will calculate the latest attenuation and ABV. The green checkbox will not be filled in until a 'Fermentation Complete' log is provided.

Brew Log

Brew log entires can show up on your fermentation chart.

Add Log Entry

Click add log entry to create a log entry.


Events marked as Fermentation Chart will be plotted on the fermentation chart.

  • Mash Complete

  • Pre-Boil Gravity

  • Boil Complete

  • Brew Day Complete Fermentation Chart

  • Fast Ferment Test Fermentation Chart

  • Sample Fermentation Chart

  • Racked Fermentation Chart

  • Fermentation Complete Fermentation Chart

  • Packaged

  • Tasting Note

  • Other

  • Yeast Starter


The system also supports Refractometer readings. The brew log entry screen is setup to correct the raw reading in two important ways:

  1. A wort correction factor must be applied that accounts for the refraction difference between sugar water and wort. To help clear up confusion with terminology, at Brewer's Friend we have decided to call a Brix measurement of wort: Brix WRI (wort refraction index). Brix WRI makes it clear the measurement pertains to wort and is unadjusted. Only after dividing Brix WRI by the wort correction factor do we arrive at the actual Brix / Plato reading. It is helpful to know that Brix and Plato are nominally the same to 3 decimal places, so the corrected reading can be treated as Plato (°P). The wort correction factor is an equipment profile option. Click here for our detailed write up on how to determine a refractometer's wort correction factor.

  2. If alcohol is present it alters the refraction by an additional factor. An equation which requires the OG must be used to correct the refractometer reading. The system displays an 'OG' box and fills in the OG automatically from your brew log. The calculator uses Sean Terrill's cubic equation.

For more information about refractometer use in general: Using your Refractometer Correctly for Maximum Accuracy in Home Brewing.