That makes sense. Thank you. So really, the “post boil” should always be the same as the batch size right? And the pre boil is the true size of the pre boil.

Test recipe shows 18.24 ABV just when adding 3kg of sorghum syrup.

https://www.brewersfriend.com/homebrew/recipe/view/870504/test-gf

Just normal fermentables. Another GF brewer said he experienced the same issue. Not sure how he worked out putting the “0” in post boil but it seems to work.

Ok i'll remember that in the future(first time poster). I was told that there is some bug in the recipe builder and if you put "0" in post boil it works fine. Not sure how i can refer this to brewers friend to fix? for the record- i did try the zero and it worked.

Gluten free extract brewer here. Recently when entering GF fermentables like sorghum/rice syrup the ABV automatically rises to around 10%. This has not happened before. Can anyone assist please.