Maxi-BIAB revisited

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Bribie G

Adjunct Professor
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My 40L Crown Urn has been playing up, but fortunately I also have a 20L Crown urn that I bought second hand off Gumtree a couple of years ago.

Since I started all grain about 9 years ago I have always done full volume BIAB in a 40L urn and my efficiency has come out around 74%

I've needed to do a couple of brews with rellies approaching in a few weeks, and a bottled stout brew I promised for a friend in Bris.
So I looked up Maxi-BIAB where the chief pioneering practitioner is our own RdeVjun. For a full rundown see the BIABrewer article that RdeV put up. To summarise, it's how to get a full gravity brew out of a smaller pot such as my 20L urn. There is sparging involved.

Using the smaller urn I did a thicker mash, hoisted the bag and drained the strong wort back into the urn and ramped up to boil.
Meanwhile did a batch sparge in an adjacent bowl lined with the bag, then re-hung bag over urn to drain with the spargings left in the bowl.

Removed bag and disposed of grain, then gradually added the spargings from the bowl to the urn in stages as the wort level boiled off.

Note my 20L urn has the same mofo 2.4KW element as the big urn so it does a good boil off.

I did the stout brew a few days ago, turned out excellent and I seemed to get better efficiency but didn't actually record the results. In any case there were sugaz additions so I didn't bother to finesse things.

So today I did a Pacific Ale, based on a recipe posted by MatPlat:

Pacific Ale
American Pale Ale

Recipe Specs
Batch Size (L): 22.0
Total Grain (kg): 4.850
Total Hops (g): 100.00
Original Gravity (OG): 1.050 (°P): 12.4
Final Gravity (FG): 1.012 (°P): 3.1
Alcohol by Volume (ABV): 5.03 %
Colour (SRM): 3.4 (EBC): 6.7
Bitterness (IBU): 43.3 (Average)
Brewhouse Efficiency (%): 74
Boil Time (Minutes): 60

Grain Bill
2.500 kg Base Barrett Burston Pale (51.55%)
2.000 kg Wheat Malt (41.24%)
0.200 kg Cane Sugar (4.12%)
0.150 kg Acidulated Malt (3.09%)

Hop Bill
25.0 g Galaxy Pellet (13.4% Alpha) @ 60 Minutes (Boil) (1.1 g/L)
25.0 g Galaxy Pellet (13.4% Alpha) @ 0 Minutes (Aroma) (1.1 g/L)
50.0 g Galaxy Pellet (13.4% Alpha) @ 0 Days (Dry Hop) (2.3 g/L)

Single step Infusion at 66°C for 60 Minutes.
Fermented at 20°C with WLP090 - San Diego Super Yeast

Note the 200g of cane sugar to get gravity up to 1050 to aim for a 5.1% ABV beer.

I followed the Maxi-BIAB steps.

Here you see the bucket sparge (Stout brew shown here) under way.

maxibiab 1.jpg

Then I hang the bag over the urn to drain, with spargings in the bowl to be added gradually.

maxibiab 2.jpg

OK towards the end of the boil, (Pacific Ale brew shown here) the level has gone down so I start topping up with boiling water.
If you look at this photo, at the end of the boil, what you are seeing in the 20L urn is basically a cornie of beer, 19L in there.

maxibiab 3.jpg

Of course there will be loss to trub and loss in the FV, so to make it up to my usual 22L brew length I'm going to need to add 3L of boiling "liquor back" water into the urn and cubes to arrive at my customary No-Chill wort volume that I know will fill a keg.

So let's check OG here with refractometer.
I've got 1.060 :)

With no sugar added yet.

So going back to the software, removing the sugar and adding 3L of water to get back to the 22L , I'll still hit the originally planned 5.1 % ABV but in order to do this, I need to spin the efficiency up from 74% to 78% and still no added sugaz. I didn't add the sugaz.

maxibiab 4.jpg

Normal no-chill cubes . Typical for a regular cornie filler.


In both Maxi-BIAB brews I have done so far, efficiency is significantly up, OGs and ABVs hit spot on with half sized equipment.

I'll do a checkup with hydrometer and again with refractometer tomorrow after cooling.
As I posted to RdeV if the 40L is not repairable I'm quite happy, on current findings, to keep using the little rottweiler urn to crank out full keg-sized brews for the forseeable.

edit: the reason I added a tad of sugar to the recipe was in anticipation that the efficiency would be lower than my full volume regular BIAB brew so the sugar was there to bridge the gap.
In fact the opposite seems to have occurred and the sugar was unnecessary.
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Well-Known Member
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Cheers Bribie, pleasing to see that the MaxiBIAB guide is still kicking goals many years later.

This method is an excellent mechanism for novice All Grain brewers wishing to step up to a larger scale 20-25L without having to invest in loads of equipment. Alternatively if they don't have much space, it is on the stovetop and in most cases the regular domestic stove is adequate, I've even done it on the lunchbox gas cooker, still with the 19L pot.

I used it for yonks, landed a national gong with a quite similar variant and only moved to a bigger kettle when a good deal came my way.


Lord Raja Goomba I

Prisoner of Sobriety
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Ferny Grove, Brisbane
Awesome work, when I came up with the 2 pots on the stove top with esky mash tun (including BIAB bag in esky with sparge in the esky) and then ghetto lauter (and the various iterations therein), it was on the back of this method and lots of in-depth discussion with RdeVjun.

Just goes to show that with thought and refinement the process of brewing can be done with minimal equipment and no major extra costs.

Loving seeing the cheap methods still doing it for new and experienced brewers.

Bribie G

Adjunct Professor
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I just oxygenated, dry hopped and pitched: after the necessary dilution the OG turned out to be spot on 1.050 as per recipe but without the white sugar "adjustment".

So from now on using the same equipment and procedure, for my 5% beers which is my normal strength I'll be able to set my eff. in the software to 78% and formulate recipes accordingly. More than happy.


Well-Known Member
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Good to see you getting good effiencey on thicker mashes.

I've regularly seen as good or better effiencey doing thicker style mashes with my gear compared to what some say you can't get with a more traditional water to grain ratio.Well you can. Plus quality is still the same .

Just got to be alittle creative and give things ago I recon despite what, apparantly doesn't work.
Sparging with thick mashes unlocks a wealth of goodness.

It's great to push into new territory and get good results.

Great stuff....

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