i did a brew on the weekend and i got 45% efficiency. i was using a new technique but it was still BIAB.
previously i had done BIAB in a kettle and it was really difficult to get the right temps and what not, not realy sure what temps it was at etc.. etc.. so i used BIAB in an esky so i could keep more solid temps, it seemed to work. hit strike temp of 66/67. it dropped down a bit, to 63 and i topped it back up. and i sparged with 75*C
i have no idea why my efficieny is so low. one idea is that i was using a hop bag from craftbrewer and the grains were quite compact in it. i tried to loosen them up etc.. during the mash. all my other brews it has been a thick liquid with all the grains floating around in it but this one it really was just the bag with the grain and the water all around it. could this be my problem??
really devo
Gerald - I hate to be blunt about it , but the reason your BiaB might not have worked out all that efficiently - could be because you have ignored a great deal of the advice about how one should go about doing a BiaB brew.
Maybe try doing it as suggested, then see what happens. One of the key peices of advice, that has been stress and re-stressed during many many posts about BiaB, is that the bag should be big enough to put your entire boil kettle inside. You are not -repeat NOT - mashing in a bag, you are mashing in a pot that just happens to be lined by a bag, the bag should in no way confine or restrict the grains. You should be able to stir, mix , measure etc etc as though the bag were in fact not there are all.
If you follow the suggested methods and if your bag is the right size and made of the suggested material, then temps are easy to take, easy to hit and easy to adjust, and you should get an efficiency somewhere around the mid 70's depending on the gravity of the brew.
I have the largest hop bag from craftbrewer - it is about one tenth the size of the bag I would suggest you make/buy for a single batch BiaB system
Perhaps that might be a start.
Stowaway - I'd stick to the basics for a couple more brews mate. You got 70-75 in your first couple of brews - thats about what you can expect from BiaB. Raise the temp to 76-78 before you pull the bag, maybe go back to that 90min mash. And see if you can start to get reasonably consistent efficiencies. Once you have a consistent technique and are getting fairly consistent efficiency numbers - then when you change something to try and do better, you will actually know whether its worked or not. At the moment, it might just be pot luck.
To get much better than 70-75% efficiency - you are going to have to start looking at "advanced" BiaB such as seemax is doing - and I just dont think that its worth the trouble when you are first starting out. Just get it to 70ish, then stick with the basic method for a while. When you are sure you are on top of it completely, then try for extra. But if you can get more than 83% out of a BiaB you beat the best I have ever done... I think Spills got 85% once - both times using a dunk sparge technique. So the best you are going to do is really around 5-10% extra. I no longer bother... its just not worth it.
Consistency is so much more important than efficiency - I really do suggest you go for that as a first priority.
TB
