Convert a BIAB recipe to all grain

[Mark Farrall]

Squeezing the bag increases volume yield, but how does it raise the conversion efficiency and/or alter the color?

Squeezing gets more of the sugar out of the bag. In standard 60 minute mashes I'd expect the gravity to go up a few SG points after squeezing the bag in my 12-15 litre batches.

Haven't heard anything about colour changing, but I wonder about roasted grain flavours tasting stronger with squeezing vs a mash vessel and sparging. It's a passing thought I have about where the tannin extraction myth may have started.

 

[Silver_Is_Money]

OK, so a rise in SG means that BIAB does increase conversion efficiency then. This old dog has just learned a new trick. It just takes awhile for them to sink in. I've been a 'mash in a cooler' guy all along, but I'm about to embark on a single kettle BIAB adventure. What sort of gloves are recommended for bag squeezing? What magnitude of yield gain can be expected? I'll need to go in with some measure of less strike water if I'm getting more out.

 

[Leukass]

BIAB is an all grain brewing method, at least most BIAB brewers use all grain recipes, so I'm not a fan of that terminology... But that's a separate issue.

All you need to do is change the "brew method" in the top of the recipe, and adjust the volumes in the mash section and adjust your equipment settings.

Thanks - going to brew recipe as is

 

[Mark Farrall]

OK, so a rise in SG means that BIAB does increase conversion efficiency then. This old dog has just learned a new trick. It just takes awhile for them to sink in. I've been a 'mash in a cooler' guy all along, but I'm about to embark on a single kettle BIAB adventure. What sort of gloves are recommended for bag squeezing? What magnitude of yield gain can be expected? I'll need to go in with some measure of less strike water if I'm getting more out.

I just use the standard washing gloves. I used to have some heavier weight ones, but they were less flexible and would end up growing mould. I've got a large sieve and a 20 litre food safe plastic bucket. I'll pull the bag and put it in the sieve on the top of the kettle. Then give it some squeezing to get the easiest wort out. Then move the sieve and bag to the bucket and leave it there while I organise anything needed before starting the boil. Then I turn on the kettle, give the bag a bit more of a squeeze and pour the contents of the bucket back into the kettle and do a final refractometer reading.

I do full volume, so don't leave anything out for the sparge. If it was a new system and I wasn't sure about the absorption rate I'd leave 2-4 litres aside and then just top up the kettle to hit the boil gravity. I'm generally not needing the extra sugar from sparging the bag, but if it's low you could always do that.

 

[Ward Chillington]

I think if I had it to do all over, I'd come back a BIAB-er...it seems much more efficient and less hardware to dick with...but I'm sure I'd over think it anyway!

 

[Sunfire96]

I use mozzarella stretching gloves, they were like $5/pair at the LHBS

 

[Megary]

Squeezing gets more of the sugar out of the bag. In standard 60 minute mashes I'd expect the gravity to go up a few SG points after squeezing the bag in my 12-15 litre batches.

Haven't heard anything about colour changing, but I wonder about roasted grain flavours tasting stronger with squeezing vs a mash vessel and sparging. It's a passing thought I have about where the tannin extraction myth may have started.

I’ve not noticed this. My experience is that squeezing the bag only helps me get to my pre-boil volume. Sometimes I have to squeeze a bit more, sometimes a bit less…but that has to do with water:grain ratio. If mash conversion is complete, I don’t understand how squeezing gets you more sugar.

I’ve never noticed any color change from squeezing, nor do I notice any flavor changes from squeezing my Stouts and Porters.

I will admit that I don’t squeeze any harder than I need in order to hit pre-boil volume.

 

[Minbari]

OK, so a rise in SG means that BIAB does increase conversion efficiency then. This old dog has just learned a new trick. It just takes awhile for them to sink in. I've been a 'mash in a cooler' guy all along, but I'm about to embark on a single kettle BIAB adventure. What sort of gloves are recommended for bag squeezing? What magnitude of yield gain can be expected? I'll need to go in with some measure of less strike water if I'm getting more out.

I get 75%+ efficiency with biab. Plus need 1 less pot

I used those heavy duty silicon oven mits at first (they do work)

But now I use an apple press

 

[Herm brews]

I “squeeze” the grain bag not with my hands, but with a couple tools. I set a colander over a 2-gallon pot, placing it right next to the kettle. After a 60 minute mash, I hold the grain bag above the kettle, allowing wort to drain by gravity. When the flow changes from a stream to a trickle, I put the bag in the colander. Using the bottom of a big spoon, I press the bag, lift a little, press, lift and press until it is obvious there is little left in the bag. With this method, I usually recover about 24 ounces of good sweet wort, which then gets added back to the kettle for the boil. The bag sits in the colander while I proceed with the brew day, and I don’t have to worry about burning my hands or getting sticky wort all over the kitchen.

 

[Silver_Is_Money]

I’ve not noticed this. My experience is that squeezing the bag only helps me get to my pre-boil volume. Sometimes I have to squeeze a bit more, sometimes a bit less…but that has to do with water:grain ratio. If mash conversion is complete, I don’t understand how squeezing gets you more sugar.

I’ve never noticed any color change from squeezing, nor do I notice any flavor changes from squeezing my Stouts and Porters.

I will admit that I don’t squeeze any harder than I need in order to hit pre-boil volume.

Now I'm rethinking this. The SG should not increase, nor should it decrease, as only the volume of Wort collected increases via squeezing. The only improvement is to Brewhouse Efficiency. No improvement to Conversion/Mash efficiency.

 

[Mark Farrall]

I’ve not noticed this. My experience is that squeezing the bag only helps me get to my pre-boil volume. Sometimes I have to squeeze a bit more, sometimes a bit less…but that has to do with water:grain ratio. If mash conversion is complete, I don’t understand how squeezing gets you more sugar.

I’ve never noticed any color change from squeezing, nor do I notice any flavor changes from squeezing my Stouts and Porters.

I will admit that I don’t squeeze any harder than I need in order to hit pre-boil volume.

The way it can add sugar is if there's a higher concentration of sugar in the bag than the wort. That won't be with all batches but can happen on some. Recirculation, a higher amount of water and a longer mash will make this less likely. I really notice it on my stove top batches, but less so with my bigger ones.

Maybe I should just be stirring more on my stove top batches.

 

[Silver_Is_Money]

The SG will increase within the bag if no mash-out step has been employed (or if the mash-out has been insufficient in either temperature or duration, or both) and saccharification was not sufficiently completed during the allotted mash cycle time. I.E., if mashing is still actively ongoing within the bag due to as yet incomplete conversion.

 

[Pricelessbrewing]

Okay so bear with me, and please feel free to ask questions or clarification.

The difference due to grain absorption rate is not really due to conversion differences, but lauter efficiency (in braukaiser terms, or in BF terms the lauter efficiency can be thought of as mash/kettle efficiency divided by conversion efficiency).

What you may not be taking into account is that when comparing two equipment and process types, you don't get "extra" volume, but rather you start with less water. Since you're starting with less water, you're result will be a higher SG in the mash. The net conversion efficiency will be around the same (assuming you don't run into issues with mash thickness or mash pH in the mashtun).

It's easier to compare side by side in my biab calculator IMO, but Doug293cz on HBT would also be a great resource for this. He helped me a ton when I was starting to integrate braukaisers efficiency formulas and mash models. I've since re-derived from first principles using a SG model instead of converting back and forth from sugar weight to brix/plato to wort weight etc etc but that could be a 10 page dissertation so I'll leave that alone for here...

In general BIABers get an average of 0.08 gal/lb absorption rate, vs an average of 0.125 gal/lb for mashtuns or process where you don't press/squeeze/suspend the grains and just let it drain without lifting.

Scenario: 1.065 OG, 5.5 gallon batch. 1 gal boil off. ~95% conversion efficiency. no mashtun losses or kettle losses. The only difference will be the expected grain absoprtion rate (and therefore the total volume of water needed).

A: Mashtun, equal runnings between mash runoff and sparge runoff volumes (this is ideal peak efficiency for a batch sparge).
12 lbs of grain, 1.55 qt/lb mash thickness.

Expected efficiencies and gravities:

Same recipe with BIAB, changing the absorption to 0.08 in my web app, with no other change.

So for this particular scenario, we can expect roughly a 4% loss in brewhouse efficiency, largely due to the lack of a sparge.

Now if we do BIAB, with a squeeze for lower absorption, but ALSO a sparge,

Here we get an even higher efficiency than the mashtun with sparge, since there is less water used in total.

 

[Pricelessbrewing]

I don't like to use terms like "sugars" in the mash because it gives the wrong impression, after the grain is saturated and converted, there really is no sugar (as in crystals). Sparging isn't "rinsing" sugars, it's diluting a sugar solution that's absorbed in the grain with water.

Think of it like a sugar solution, or pot of juice, and the grain is a sponge.

The juice absorbed in the juice is the same density (SG) as the juice loose in the pot, always. If your sponge absorbs less of it, then the amount of juice you need to start with is lower, and you can get a higher SG from the same amount of grain. The trick to this is that the total volume of wort (juice) is NOT the apparent loose volume in the pot, but there is some non insignificant volume aborbed in the grain, on the order of a half gallon or more per 5 gallon batch. That volume is non-linear and is pretty complicated to derive and calculate, but once you know the expected SG of the mash, then it's all just basic dilutions of that total true volume.

You absorb, some of the total true volume is released, but the SG doesn't change. If you sparge, you add to the total volume and the SG is diluted linearly (in reality sugar solutions aren't REALLY linear dilutions, but that's on the order of 10-100x more precise than a standard hydrometer so it really don't matter).

 

[Silver_Is_Money]

Indeed it is a complex subject that is well above my pay grade. But if Doug293cz is involved, I'm certain the programming logic is the best it can be.

 

[Minbari]

makes sense. So all Tanin discussions aside, Squeezing it is!