How much does your efficiency vary?

[Andrew R]

What I'd like to know is, over the course of many brewdays, how much do people's mash efficiencies vary? I don't so much care about the number you get - but just how much it varies from one batch to another. Are you always getting the same efficiency? Or do you get somewhere around a percent or two or more out? 

I ask because I've been doing BIAB for close to a year now. But that's not as much an achievement as I'd like it to be as work has been seriously busy and got in the way of brewing. So I've only managed to find the time for 6 or so brews. But my efficiencies are wild. Now I suspect my technique with BIAB - because I think that I'm not all that disciplined. From brewday to brewday I treat the bag juat subtly  differently each time ( I'm sure I must squeeze harder one day than the next - hold it over the pot a fraction longer the time after to drain it more). And as such, I'm converting an old chilly bin into a mashtun and I'm going to start batch sparging with a view to eliminating the number of variables I encounter with my current process. But I am wondering if I'll be able to expect a much more predictable brewday - or do I just tinker too damn much?

[Patrick]

I BIAB and my efficiency hyovers around 70%. My main variable is boil-off rate, can't seem to get that right half the time and end up needing to top up with tap water in the fermenter.

[Mike Neilson]

This is what I usually get

1.040-1.070 80% With Kolsch 92% With Golden Promise after 1.070- to about 1.085 its about 5% less and I hit anything from 65% - 75% with anything over 1.090.

[JoKing]

Yeah - I find that as the grain bill increases in volume, the efficiency decreases. Add to this different base malts which have higher / lower potential extracts compared to each other and your efficiency will become quite variable.

With a bit of experience, you can predict what your efficiency should be - this way it doesn't matter if it swings around a bit.

[MrC]

I too find that my efficiency decreases as the grain bill increases. For my typical 5% beer I get around 72-75% every time.
The only exception to that are my wheat beers (60% wheat) where my efficiency drops to 60-65%.

NOTE: My percentages are for brewhouse efficiencies.

[Mike Neilson]

Same as me so if I brew a beer and the total volume at end of boil is 23L and say if I use 5kg of grain I would get about 1.060.

[JackoNZ]

I BIAB too. My mash efficiency varies depending on malts used. Munich and ADM pils get me around 75-78%, malts like Maris Otter, Golden Promise and Pearl Pale get me around 82-85%. My brewhouse efficiency varied a lot more but is on the up as I have worked on my sparging technique.

Using a spare bucket to sparge, I'm now letting it sit there for 10 mins before dunking and draining and adding to the boil kettle. I now measure my volumes and gravity readings at each point in the process which is also helping me hit numbers, i.e I expect x amount in the boil kettle after the initial drain, this means I know I am squeezing the bag to the same formula each time. I measure the gravity at that point too. Taking a gravity reading of the first sparge before adding back to the kettle again allows me to work out how much I'll be diluting what's already in the kettle and giving me a good idea if I'm close to hitting my expected pre boil gravity.

For what it's worth I use a 1:1 formula for squeezing the bag, so 5kg grain bill means I will initially drain the bag over the kettle until I have lost 5L of wort from the original volume. Then I sparge until I hit my pre boil volume/gravity or better.

[Tony]

My efficiency rates have varied between 65-79%. Since I changed my mash tun, to a narrower, deeper model (warehouse chillibin), my efficiencies have improved. I have found a few factors improve my efficiency:
-longer mashes
-batch sparging as opposed to continuous
-better malts (I generally use MO or Weyermann pilsner as base malts)
-making sure I have stirred the mash well
-2 stage mashes (55/68)

generally a combination of any of these, has improved my efficiency. I empathise with you Andrew. If you don't have the time it is difficult to do it well. It is a time demanding excercise and you need to be able to controll the critical phases in order to get it right. I don't find it too dificult, to manage once you've go your system down and you don't want to play with the mash once it is set.

[James P]

I'm with Tony on his improvement factors for traditional mashes. My efficiency sits in the 80's now, when I BIAB it was wild between 60 and 80%.

[Andrew R]

Thanks for the empathy. Definitely being unable to brew quite as often has had it's disadvantages. But how's this for a sob story - I've moved house recently as well and misplaced my old brewsheets so I can't reliably remember everything I did. When I say misplaced, I mean the wife binned them at the same time she threw away my remaining 150 odd grams of hops because they were "stinking up" the chilly bin and she thought something feral was in there. Plus being a computer geeky sort I've upgraded the pc a couple of times in fairly major ways so my beersmith records weren't something I treated as a priority.

But thanks for the comments. Definitely it sounds like I've been experiencing something fairly normal. Maybe I need to brew more or less the same beer a few times until I nail it repeatedly, and then be confident in the technique.

[jt]

Stability and repeatability in process is the key - and probably a good understanding of what's happening and why
I have the first, but not the second

I have about a 3 percentage point range
If I vary grain bill or grain:liquor ratios significantly (very rare) it can go to 5 points.

[denimglen]

"Stability and repeatability in process is the key - and probably a good understanding of what's happening and why..."

Agreed. As you mentioned Andrew R reducing variables makes things a hell of a lot more predictable and easier.

Typically your efficiency will be all over the show for the first 10 batches or so as you get a feel for your equipment, the processes, etc.

Make sure you're getting analysis sheets for the malts you use and use the figures in that to calculate your efficiency.

Your efficiency into the kettle will always decrease as your expected OG increases - it's due to the reduced ratio of sparge water to grain. You can increase your sparge water to compensate but this will require a longer boil, and sometimes it's cheaper/easier to throw in some extra grain than to boil for longer.

What's interesting as I've been a bit more in-depth calculating my efficiency lately no matter the grain bill size/OG I'm pretty much always getting 97% +-1% mash efficiency (percent of available starch that was converted). So this really shows that the inefficiency is in the lauter.

But to answer your original question, 69 to 72% brewhouse efficiency for beers from about 1045 to 1060.

[Andrew R]

"Make sure you're getting analysis sheets for the malts you use and use the figures in that to calculate your efficiency"

I actually downloaded the set of info you put up a while ago for importing into beersmith. But how often would you say that info would need to be updated? I'd imagine at least once every growing season is a bare minimum...?

Anyway, I'm definitely going to go the way of reducing the variables. I figure with the converted chilly bin my handling of the brewday has to improve -- how many things can I be screwing up then huh? :-)