BIAB for low alc beers: sparge, addition, pH

[NeoY2k]

Hello,

I tend to like low alcool beers, about 3% north England style, and have had pleasing results brewing beers in the 1%-2% alc range. Call me pussy xD but that’s how I like my beer.

I do BIAB but am wondering if I could get better efficiency (I have bad efficiency) and maybe better beer by sparging the bag and / or doing water addition.

If I mash full volume I can end up over 5l/kg mash ratio which is way over industry standards. BIABers don’t usually seem too concerned about full volume mashing, but it might be overstretching it in the context of small beers. PH might be dropping below reasonable which might contribute to bad efficiency. And beer might be better if I mash with lower ratio.

So If I decided to mash BIAB at a more reasonable 3l/kg ratio. Then sparge the bag with some (calculated) water, not too much to avoid too low sparging ph. Then add the rest of the water directly to the wort. All that ending at the desired pre boil gravity.

May I improve brewing efficiency and improve beer quality?

I seem to not think about anything bad about it, but I might be wrong.

Your opinions are welcome

Thank you,
Nicolas

 

[RM-MN]

Thoughts:
1. Low efficiency is usually caused by a poor crush. All other factors are far below that.
2. Sparging will gain you between 5 and 10% efficiency.
3. Using cool water for sparging eliminates the chance of extracting excessive tannins. To extract the tannins requires temperature over 170F and pH over 6.0. If one of those factors is missing you don't get tannin extraction.
4. If your beer has high enough OG to suit you, topping off the wort after the boil is a viable option as it begins cooling the wort. I wouldn't dilute the wort preboil. Instead, reduce the base malt so you don't have as much sugars to extract.
5. Industry standards be damned. From studies I have read, the thinner your mash, the higher the efficiency. There may be a limit on that but nobody has reported it.

 

[DBhomebrew]

If you're going to sparge (I do), do a properly performed dunk sparge. Fully drain, dunk, fully drain. For highest efficiency*, aim for half (40-60%) of your preboil volume to come from each draining. A pour-over is nearly impossible to do effectively.

In addition to using cool water to prevent tannin extraction, using RO or otherwise low/no mineral water will have no buffering ability and therefore will not pull pH out of range.

*High efficiency should not be your first goal. Repeatability should be. Repeatability in process brings predictability in product.

 

[kevin58]

You can usually squeeze out a handful of efficiency points by 1) milling your grains finer. If you have your own grain mill try setting the gap at something around .028 to .024. A set of inexpensive automotive feeler gauges will help you get a precise gap setting. 2) Squeeze the bag. I mean squeeze the living crap out of that thing and wring out all the sugary goodness.

PS. mash efficiency has nothing to do with making better beer. And adding water to your wort after mashing will only dilute the wort and end up lowering your overall efficiency.

 

[mac_1103]

adding water to your wort after mashing will only dilute the wort and end up lowering your overall efficiency

Why would diluting the wort after mashing to compensate for a high boil off rate or to lower the ABV have any impact on efficiency? The only thing that should impact efficiency after mashing and lautering is leaving sugary wort in the kettle. If the same volume of wort is left behind in the kettle, then wouldn't efficiency actually be higher if that wort is more dilute?

 

[doug293cz]

Why would diluting the wort after mashing to compensate for a high boil off rate or to lower the ABV have any impact on efficiency? The only thing that should impact efficiency after mashing and lautering is leaving sugary wort in the kettle. If the same volume of wort is left behind in the kettle, then wouldn't efficiency actually be higher if that wort is more dilute?

^^This^^ is correct. The more dilute the final bit of lautered (drained) wort, the higher the efficiency. Once all wort from the mash is in the boil kettle, dilution does not change mash efficiency, whether done pre-boil, during boil, or post boil.

Dilution in the boil kettle will increase your brewhouse efficiency a bit, since you leave lower SG wort behind during the transfer to the fermenter (not applicable if everything in the BK goes into the fermenter.)

Brewhouse Efficiency = Mash Efficiency * Volume in Fermenter / Post-Boil Volume​

= Mash Efficiency * (Post-Boil Vol - Vol Left Behind in BK) / Post-Boil Vol​

Brew on

 

[NeoY2k]

Thank you.
That cold sparging is a welcome trick.

Still if anyone has opinions on say 3l/kg vs 6l/kg re: pH and beer quality I'm all ears.
Classic wisdom re low abv british ales is more towards the "brew with low ratio then sparge a lot" but how much of that is science based...

 

[Halfakneecap]

Thank you.
That cold sparging is a welcome trick.

Still if anyone has opinions on say 3l/kg vs 6l/kg re: pH and beer quality I'm all ears.
Classic wisdom re low abv british ales is more towards the "brew with low ratio then sparge a lot" but how much of that is science based...

I brewed BIAB for years and mostly brew 3-4% beers. I often brewed full volume. I generally had pretty good efficiency and brewed lots of UK ales with no issues to me.


I'd still sparge definetely if mashing thicker. I prefer 90c sparge water but that's not a rule you need to follow.

 

[Ramjet]

I Biab using a Wilser bag and multiply the amount of grains in pounds by .08 and add that number to my desired pre boil volume for a full volume mash.
Example: 10.5 lbs × .08 =.84
6.5 ( pre boil volume) + .84 = 7.34 gallons for full volume mash. My efficiency is in low to mid 70%

 

[mashdar]

Why would diluting the wort after mashing to compensate for a high boil off rate or to lower the ABV have any impact on efficiency? The only thing that should impact efficiency after mashing and lautering is leaving sugary wort in the kettle. If the same volume of wort is left behind in the kettle, then wouldn't efficiency actually be higher if that wort is more dilute?

Maybe he was trying to say that efficiency would be higher if all water went in the mash, either as full volume infusion or extra sparging.

But it sounds like Neo would overflow mash tun if attempting full volume infusion. It also sounds like Neo doesn't want to treat sparge water, and is avoiding high sparge pH by limiting sparge volume (Neo knows some stuff!)

Does sparge pH matter if you do a cold sparge? I wouldn't think so? Maybe lazy = better. edit: oops, I need to read harder. : )

 

[mac_1103]

It sounded to me like Neo just didn't want to mash too thin. I didn't see anything about overflowing the mash tun. But I guess he never really said whether he was mashing in the boil kettle or a separate tun.