Biab conversion

[Marcusp]

I've just converted to biab and have a 70 ltr pot
I have the gw book and on putting my first 19 ltr gw recipe into the calculator on the biab forum with the quantities shown in gw book. When I enter final liqueur quantity of 19 ltrs into the calculator it ups my grain bill by approx another 500g.

Just wondering if this is right or have I done something wrong as I was expecting the grain bill to stay the same and just use the calculator to work out my total liqueur volume.

The only thing I can think of is that it ups the grain bill because of the lower efficiency of around 75% in biab.

Should I go with the calculator or stick to the recipe in the book ?

 

[Smiddylad]

The problem is your guessing your efficiency, so you are never gonna know until you've done a couple of brews and calculated your true efficiency. Personally I would start lower at 70% and take it from there, but that's me in my brew house. Just out of interest a friend once told me that you should increase your grain bill by 5% when doing a BIAB brew, that's too much of a generalization in my opinion, but worth mentioning. Anyway long story short I would always go with the calculator as it should be more tailored to your needs.

Neil

 

[Marcusp]

Cheers Neil I'll start with what the calculator says then ?
Can you tell me how I calculate my efficiency ?

 

[Smiddylad]

Hi Mate
I use this link, which makes it easy. Only issue is it limited to 6 types of grain.

http://www.brewersfriend.com/brewhouse-efficiency/

Also John Palmer talks about it here much better than I ever could.

http://www.howtobrew.com/section2/chapter12-5.html

Good luck

Neil

 

[Marcusp]

Cheers mate always wondered how it's done and now I know