Grain efficiency

Make grain beers with the absolute minimum of equipment. Discuss here.
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Rookie
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Grain efficiency

Post by Rookie » Sat Jul 27, 2019 6:51 pm

Had anyone out there switched from regular all-grain to BIAB?
How was your efficiency changed?
I'm just here for the beer.

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vacant
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Re: Grain efficiency

Post by vacant » Sun Jul 28, 2019 9:14 am

8% drop in it's purest form.

I've just done AG brew #99 which was BIAB. I started AG using BIAB way back in 2008 and also regularly use a conventional 2-vessel AG thermopot mash tun. Long ago, I tried to work out some sort of theoretical basis and kept this calculation:
Initial assumptions:

1) 35 ltr total liquor
2) 5 Kg of grain in the mash tun
3) when drained the grain retains 5 ltr of wort
4) result is 30 ltr into the boiler

BIAB

Add 35 ltr full volume and do the mash
Once fully saturated 30 of the 35 ltr can be drained i.e 30/35 = 86% of sugars get to the boiler
The wort in the grain retains 14% of the sugars

Two Stage Batch Sparge

Target is to sparge two lots of 15 ltr
Add 12.5 ltr, mash then add a further 7.5 ltr (total 20 ltr) for the first sparge
Once fully saturated, 15 ltr sparged, 5 ltr retained in the grain so 75% of the sugars got to the boiler
25% of the sugar remains in the grain because 5 ltr of wort remains in the grain
Add the remaining 15 ltr to the mash tun, back to 20 ltr liquor
Once fully saturated we can drain 15 out of 20 ltr (15/20) but that wort contains a quarter (5/20) of the sugar so 15/20 * 5/20 can be drained = 19%
The boiler now has 30 ltr with 75% sugar from the first sparge and 19% from the second sparge = 94%
The wort in the grain now retains 6% of the sugars
BIAB efficiency can be improved by holding back some liquor and running that through the bag (like doing a bit of fly sparge) and squeezing the bag. These both add a bit more time and effort and the main advantages of BIAB are simplicity and time (it was a nice day on Thursday, the NC750X was sitting there begging to be taken out for a ride), my brew was all done in 3 1/2 hours as I did a no-chill too.

Rather than faff around I just chuck in a couple of handfuls of extra grain.
I brew therefore I ... I .... forget

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PeeBee
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Re: Grain efficiency

Post by PeeBee » Sun Jul 28, 2019 11:56 am

Since my big (70L) three vessel brewery started getting some modifications in November 2018 I've been using "BIAB" techniques - well not exactly BIAB but emulating BIAB, or copying "full-boil-volume-mashing" in a Grainfather. Initially for "low-alcohol" beer brewing, but more recently all my brewing because it's so straight-forward and easy. There's some piccies of me doing it last week just here: viewtopic.php?f=12&t=81739&start=66 (ignore that this is a "cold" mash).

I don't notice any reduction in efficiency and have gone back to using 75% brewhouse efficiency for the calculators as before. Obviously I can't squeeze the grains in a GF, but a GF does drain the grain very well. I do not try to "sparge", but as space is a premium in a GF I'll retain any calculated water that wouldn't fit in the mashtun and pour it on at the end (up to about 3L, but I've been keeping SGs below 1.058 and 20L batches - a GF has a 30L capacity). I also learnt from this that the temperature of the "sparge" water isn't really important like I used to think it was.

I think the reason I notice no loss of efficiency is what I might lose in mash efficiency I easily make up for from increased overall brewhouse efficiency. Maybe recirculation is keeping my efficiencies up too?

My big brewery will be running again soon, but it has a 70L mashtun so I might yet continue my "BIAB emulations", or even some full-on BIAB as it's got a 100L boiler. BIAB just makes so much more sense.

Annoyingly I notice there is still a 2017 article on the Grainfather Web site suggesting traditional "sparge" brewing techniques makes better beer than "full-boil-volume-mash" techniques (which is what BIAB is). It is complete bolloc...

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PhilB
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Re: Grain efficiency

Post by PhilB » Mon Jul 29, 2019 12:13 pm

PeeBee wrote:
Sun Jul 28, 2019 11:56 am
I think the reason I notice no loss of efficiency is what I might lose in mash efficiency I easily make up for from increased overall brewhouse efficiency. Maybe recirculation is keeping my efficiencies up too?
... erm, point of pedantry PeeBee ... but earlier in the post you've said you "don't notice any reduction in efficiency and have gone back to using 75% brewhouse efficiency for the calculators as before", so your "overall brewhouse efficiency" has remained constant, neither increasing, nor reducing [-X

Rookie, coming back to your question, you probably need to consider and explain what you mean when you say "BIAB" ... but in terms of comparing some of the features of (the various "flavours" of) BIAB that may have an impact on efficiency (depending on whether you deploy those features in what you do) and how they effect efficiency ...
  • I believe constant recirculation throughout the mashing period is recognised as increasing mash efficiency, and your efficiency can never be any higher than it is at the end of the mash, losses mean it's all downhill from there;
  • but then not sparging when you BIAB, if you're going to do full volume, "true" BIAB, increases losses (because higher gravity wort is "lost" when it's left soaked into the spent grain, than would have been had you sparged);
  • there are no lautering losses (other than those due to wort taken out in grain) with BIAB, no deadspace at the bottom of the mash-tun, no wort left in pipes used in the transfer;
  • and boiler losses (due to deadspace, wort soaked in hops and lost to trub and lost in transfers) will be similar whether you BIAB or multi-vessel (for the same boiler)
... so, if you don't recirculate and don't sparge, you'll get a reduction in overall efficiency (like vacant indicates), if you recirculate and sparge (like some people do with BM and GF type systems ("Brew in a (metal) Bag") you may well improve overall efficiency by similar amounts, and if you do something in between (like PeeBee) you might get "in-betweenie" overall efficiency :?

Cheers, PhilB

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Re: Grain efficiency

Post by Rookie » Mon Jul 29, 2019 5:54 pm

By BIAB I mean my grains in a bag in less than the full amount of water, lifting the bag out and running some water through the bag to get up to full preboil volume.
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Re: Grain efficiency

Post by PeeBee » Tue Jul 30, 2019 8:23 am

PhilB wrote:
Mon Jul 29, 2019 12:13 pm
... erm, point of pedantry PeeBee ... but earlier in the post you've said you "don't notice any reduction in efficiency and have gone back to using 75% brewhouse efficiency for the calculators as before", so your "overall brewhouse efficiency" has remained constant, neither increasing, nor reducing [-X
Pah, and fiddle faddle. I was using my Poetic License to be a tad less than accurate … here's a copy of my license:
Poetic License.jpg
Poetic License.jpg (2.47 KiB) Viewed 255 times
Now let me see your license for pedantic harassment …

Naa. Stick that in yer pipe and smoke it.

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PhilB
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Re: Grain efficiency

Post by PhilB » Tue Jul 30, 2019 10:03 am

PeeBee wrote:
Tue Jul 30, 2019 8:23 am
Now let me see your license for pedantic harassment …
... I need no license ... but, I'll not even bother to point out the lack of validity and lack of poetry in your license :wink:
Rookie wrote:
Mon Jul 29, 2019 5:54 pm
I mean my grains in a bag in less than the full amount of water, lifting the bag out and running some water through the bag to get up to full preboil volume.
... then I'd suggest you assume a reduction of around 5% brewhouse, but be prepared to liquor-back to OG if your sparging makes the reduction less than that :?

Cheers, PhilB

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Kev888
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Re: Grain efficiency

Post by Kev888 » Tue Jul 30, 2019 1:19 pm

Rookie wrote:
Sat Jul 27, 2019 6:51 pm
Had anyone out there switched from regular all-grain to BIAB?
How was your efficiency changed?
It isn't really grain efficiency in this context, the grain just has a certain potential. The efficiency is instead down to our processes - so it depends on which stage we are talking about; generally either mash efficiency (including the sparge if there is one), or brew-house efficiency.

Unfortunately efficiencies as reported around the internet are generally poorly calculated, misunderstood or downright fabricated (people brag, as if it validates their brilliance), so getting a handle on what is good, normal or bad is difficult. It also varies with things like the OG (higher gravities tend to be less efficient), absorption to different amounts of hops and so on.

FWIW, for me full-volume (true) BIAB mashes come in at very roughly 70% mash efficiency. A slightly crude dunk-sparge tends to take them to around 75%. One can get more, but if efficiency rather than convenience is wanted then I use a different method.

In terms of the drop in efficiency, it depends on what the comparison is against. A full-volume BIAB mash is actually quite a lot 'more' efficient than the true no-sparge mashes I've done (which are not full-volume mashes). Conversely, it is not far off 30% less efficient than slow and careful fly-sparged brews.
Kev

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