Braumeister 20L + BeerSmith = actual BIAB Grain Absorb is 0.8534

[neal.p]

Hi,
I'm trying to nail down an efficiency problem from the last five or so brews. I'm consistently 10 points lower than I should be (e.g. 1.060 not 1.070) on a BM20. I'm using a Brewhouse Efficiency of 68% at the moment but the last brew was 66.3%.

On my last brew, Beersmith calculated the following pre-brew:
= 36.11L total water
= 5.74kg grain
= 3.51L grain absorption
= 32.60L avail from mash.

but I actually got...
= 5.11L water absorption
= 31L avail from mash

So post-brew, my actual BIAB Grain Absorb is 0.8534 fl/oz and not 0.5860 fl/oz.

For boiling, my actual evaporation rate was 6.1% (not 13%) with only 1.89L evaporation per hour (not 4L). So my volume into fermenter was fine.

I use 27L post boil because of losses to fill two 10L fermenters. About 11L in each. This allows 24 x 750ml bottles = 18L (batch volume) without picking up much trub etc..

I crush grain at 1mm or 1.2mm with a MashMaster Mini. Is the high grain absorption because my crush is too fine or coarse? And I do a iodine conversion test.

I use the BacBrewing Increase disk so maybe the pump isn't powerful enough to flow wort through the grain to the top? On my next batch I'll check what the temp of the wort is on top of the malt pipe.

If you guys have any tips on how to fix this, it would be great.

Thx,
nealek

 

[Coalminer]

My method is usually 26l mash and 7l rinse/sparge with a 1.5ml crush and 90 Min boil
Brewhouse efficiency always over 80%.
Sorry, I don't use Brewsmith so can't help you there

 

[MHB]

Apart from the very strange Grain Absorption figures (fl/oz FFS), 0.96L of water absorbed by 1kg of grain is pretty standard (can vary a bit depends on how long it sits to drain, gets pressed/squeezed...)

Low efficiency in a Braumeister can really only be down to two factors
Temperature - the sensor can fail and mashing at radically different temperatures can lead to some strange results. Put the BM in Manual mode, put around 10L of water in it and set it to say 65oC and leave it running for half an hour or so with the pumps on and check the temperature (given you have a reliable thermometer).

Malt - this is really the most likely answer. The freshness of your malt, the way its milled (not to fine and not too coarse see Goldilocks). Too coarse and you wont get the extraction you are looking for, too fine and you will get dough balls and very slow or even no water going through the malt (just overflows).
As you are milling your own it probably means you are storing malt, chew some if its isn't crisp and crunchy its what is called Slack, taken up moisture, and lost most of its enzymes, so you wont get the conversion you expect. Comes down to poor storage - not airtight.

Really I think reading your post you know most of this

Braumeisters rarely hit 10%/hour evaporation, I talked to one of the design engineers about this and he said it was deliberate - to avoid boilovers and getting sued when people burn themselves. You could insulate the body of the BM, that will up the evaporation, boil longer (as Coalminer) about 90 minutes was always my default for just this reason.

If you think its the BacBrewing Increase disk (haven't seen one so guessing) you could try a run without it or just turn off the pump and see if the wort is draining down through the grain rather than just sitting on top(more to do with the malt than the Disc)
Mark

 

[neal.p]

Thanks Coalminer. I've read varying reports about sparge water temp...some just use it right out of tap. What temp do you use?
I've started using a 15min 79c mash out (to see if it helps efficiency). So I wonder if 79c sparge water, rather than 76c, would be the way to go.
Might try a larger crush. I thought I might have a pic of crush but I don't...

Thanks MHB. It's odd that BSmith uses fl/oz even when metric settings are used. The default for BSmith BIAB is 0.586.
Good tip on checking temp sensor. Malt was from Sydney bulk buy last year...maybe five months old now. Gravity has been 10 points lower since I started using this grain. But it was also the point when I switched to crushing my own. I'll widen the rollers and see.

 

[MHB]

Try putting a couple of hands full of malt through the mill, adjust until the grains start to just look opened up. Nip the mill up a touch more and run the grain through twice.
If you took a cup of malt, double crushed it and put it in a kitchen strainer and sift out any flour, there shouldn't be more than a dessertspoon full of fines. Tip the grain out and sort through it, there shouldn't be any uncracked grain. Occasionally there will be a very small corn (individual grain) these don't count.
If you are having trouble seeing if the grains are intact, pour a couple of hundred mills of boiling water on the grist, let it soak for 30-60 minutes. Then sort through it, any grain that wasn't cracked will swell up and be very obvious (pearls).

Even good malt if it isn't cracked properly wont give good yield. a bad crack can cost you 20% extract yield, get it back every 5th grain bill is free. A Braumeister needs a very permeable grain bed.
Mark

 

[MHB]

Snip
It's odd that BSmith uses fl/oz even when metric settings are used. The default for BSmith BIAB is 0.586.
Snip

A while ago I was looking at an American (maybe Canadian?) recipe book, they had both silly system and metric quantities for everything. good I thought, until I realised all the bitterness was expressed in HBU - which only males any sort of sense in pounds shilling and pence.

I often suspect some American writers aren't even aware of an alternative - just for fun Google "Countries that use Imperial Measurement" its a fine and exclusive club!
Mark

 

[neal.p]

haha, great image!

Thanks for the crush tips. I was actually putting 100g through as you were writing. Pics are below. I'll follow the other steps tomorrow.

1.2mm crush

1.5mm crush

 

[neal.p]

Double crushed 2 x 124g

1.2mm // 14g dust // 11.3%

1.5mm // 8g dust // 6.5%

 

[MHB]

Try going through twice at 1.5, shouldn't increase the fines too much, but will detach a lot of the husks and catch some that were facing the wrong way first time through.
Mark

 

[Coalminer]

Hi Neal
I always mash out at 78C and have my sparge urn set at 79/80C
Saying that note that I mash in at room temperature and ramp up to mash temps
Temperature probes are a problem with these things, I am on my 3rd probe and it reads 2C higher at all temps so have to adjust accordingly

 

[neal.p]

Thanks. I've just started mashing in at room temp. Just checking probe now.

So I added boiling water to two lots of 124g grain.
1.2mm weighed 261g with 3g of uncracked (1.15%) - most were smaller or discoloured.
1.5mm weighed 240g with 2g of uncracked (0.83%) - most were smaller or discoloured - but there were double the number.

1.4mm Double crack // 122g Grain // 10g dust // 8.2%

 

[neal.p]

Brau temp seems fine. Set for 65c. It varied from 64.5 to 65.5 randomly measured over half hour.

 

[Talnoy]

If you are having trouble seeing if the grains are intact, pour a couple of hundred mills of boiling water on the grist, let it soak for 30-60 minutes. Then sort through it, any grain that wasn't cracked will swell up and be very obvious (pearls)

Thanks a lot for this! I've been crushing (in my case milling ;-)) at 1.2 mm for a long time and I have had a lot of flour and what I thought was a quite a lot of uncrushed grains. I couldn't understand it, so I let it be and just accepted it. I got an MM3-grainmill with a fixed gap between two rollers and then an adjustable gap between another pair of rollers. I measured the fixed gap today (why haven't I done this before???) and it appears to be 1.6 mm wide (which is what Speidel recommends (https://www.speidels-braumeister.de/en/beer-brewing/tips-and-tricks.html)). Just to make some difference, I set the adjustable gap to 1.5 mm and crushed some grains with it. I soaked the crushed grains in boiling water as you write and noticed that the grains I thought were uncrushed, actually are crushed, but the husk is intact and seems to keep the core together. The grist contained a small amount of flour and a couple of uncrushed grains, but for me this amount is neglectible. I really look forward to brew with a 1.5 mm grain bed and see what happens with the efficiency./Joakim