Problem Solving: Terrible Efficiency

[labels]

I BIAB with a pot and a 3ring gas burner and apply direct heat without issue. Some use cake racks to lift the bag from the floor - I don't bother and just ramp up a bit slower.

I use a full volume method, with a liquor to grain ratio of about 7:1. Your ratio for this grain bill was about 3.5:1 which is getting into the realms of traditional ratios in a 3V system. Only you're not using a traditional sparge and bigger bills are notorious for lower efficiency (and while you pour water over the top - you don't have a proper grain bed - I'll wager you're getting massive channelling and really not getting anything out of it). A dunk sparge might work - but I've tried half a dozen variants to BIAB (dunk sparge, infusion mash out, what you do with lifting the bag and pouring water through it) and I get far more consistent results with full volume, proper temperature and a mash out.

I think Labels was right about one thing, your LHBS is doing your crush so it's something that may be affecting and outside of your control.

Funnily enough this thread has been going the same time as the mash schedule thread in which Bum posted this link;

http://aussiehomebrewer.com/topic/54273-rack-for-biab-any-ideas/page-2#entry897732

Which is a pretty straight forward assessment by TB. If you want to understand more though I find braukaiser a great reference - It has a good balance between science and writing it in a way poor old me can understand. In particular the section on Ezymes and Starch conversion.

That makes a lot of sense - a Lot of sense so he should be able to sort the problems from here

 

[Rowy]

You must be using a hell of a lot of sparge water and must have been aiming for a very high OG. I've done roughly 70 BIAB brews in the craftbrewer 70 litre pot. With that much surface area I get about 15% boil off if not a bit more. Do you get a decent boil going Spiesy? I just crunched the numbers in Brewmate using my standard numbers and at 65% I get an OG of 1.081 and ABV of 7.86 and it tells me to use 38.86litres of strike water. I also do a sparge using a bucket in a bucket system but use only about 4 to 5 litres of 90 plus degree water as my efficiency goes out the door if I use more water to sparge than this.

 

[Rowy]

Forgt to add I mash out by rasing tempt to 78dgs whilst stirring constantly. I use a cake tin to keep the bag off the bottom when I am doing this. This definitely increases efficiency.

 

[felten]

I find it odd that some members are recommending I raise the temp of the mash, with using BIAB... unless I have some sort of protection in my pot (which I don't), I'll run the risk of melting my bag - wouldn't I?

Nah, if you stir constantly you will be fine. I use a spiral burner and often have it going full bore with the bag in there, no burnt bags so far.

 

[Crusty]

I've got the same roasting rack as Bribie in my urn to keep the bag off the element.
Raising temp from a 90min sacc rest to 78deg for the mash out really boosts efficiency with the full volume mash. ( constant rousing of the mash whilst heating )

 

[stakka82]

Crush size is a big one in my experience... I go to powder for biab and always hit 80% plus.

A couple times I have gone a fair bit coarser and end up in the high 60s or low 70s.

 

[MastersBrewery]

when BIABing I use an OTS for stepping to mashout, stir with it constantly so no scorching