Help ! How to calculate extract potential for a grain ?

[atomicgarden]

First of all, hi everyone ! New member here.

Here's my problem. I like to calculate the mash efficiency of our brew-house for every batch we try. So far, we've only brewed beginner brews, so the malt bill were fairly simple. I never had trouble finding the ppg for the grains we used so far. I've been looking at different charts I found online (BYO, Beersmith, brewunited grain database etc.) Now, I know the extract potential can vary depending of the brand and also from different crop. I'm a perfectionist, but I'm not gonna obsess if I found a 0.001 differences between the sources I've been using. For exemple 2-row is pretty much always at 1.036 everywhere I looked, so I used this number.

Now that we're trying our hands at beers with bigger malt bills, I have trouble finding the right ppg for some of the specialty malts we need to use. For exemple, I've been searching for Gambrinus honey malt and I've seen a lot of different numbers. From 1.034 to 1.039, so what gives ?

How can I calculate this myself ? I've found specs and I can find out what's the max moisture % and the extract FG %, but what's the right formula ? I've tried researching it and I found a couple of different formulas. Homebrewers don't seem to agree on what's the right formula to calculate the ppg of a grain. Please help me out !

For the record, I want the ppg for the following grains :

Pale Wheat (Weyermann)
Flaked oats (oio)
Honey malt (Gambrinus)

Thanks !

 

[Qhrumphf]

If you can get the data (easy when buying by the sack- for example all Weyermann sacks have a lot number and QR code linking to malt analysis for that particular lot, harder to do buying by the pound) it's easy to calculate PPG from % extract

http://www.morebeer.com/brewingtechniques/bmg/noonan.html