Brew Efficiency

Replies to This Discussion

Permalink Reply by Peter Smith on February 7, 2014 at 11:44am

Is there a good document that explains all the different eff numbers?    In Beersmith there is an est total eff number to help get grain bill right for OG mine I change to 78% and I normally get about 1-2 points off desired FG, which is prob within my margin of error anyways.      When I enter the actual OG I got and L into fermenter in the lower RHS panel I also get about the same number over last 4-5 brews.   BS has mash eff at 90% and I cant change this - perhaps in another place.

Would be a great evening to have a beersmith guru present all there tips tricks and tuning process....  Do we have a guru in the house?

I used to get way lower the changes are,  I now have my own mill and I mill a WHOLE lot finer then I have got from a store.  I will take some photos next brew, before I got my mill I used to beef up the base malt by AT LEAST 1/2 kg to hit my numbers.    I didn't really bother sparging as much as the thick grist didn't "hold" water it gushed through, now I can sparge.  

Do you monitor the gravity before and during the sparge to see how it changes?

I use BIAB and about to try a 10gal cooler , I assume this will massive change everything for me.......

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Permalink Reply by Crusader-Rob on February 7, 2014 at 1:18pm

I also BIAB and like the simplicity of it, time saving etc.

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Permalink Reply by Grant R Baker on February 7, 2014 at 2:51pm

Mash Efficiency in Beersmith is changed in Equipment profile....

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Permalink Reply by Grant R Baker on February 7, 2014 at 2:49pm

Grain crush and leaving the mash long enough to complete really helps. Also check the temperature in random places in yer mash to ensure the temp is uniform(ish).

I read a while ago the efficiency for mashing was... but I have tried all three and get the same results (about 75%) for batch and fly, but BIAB was higher (nearly 80%).

70-75% for Batch sparging

75-80% for BIAB

80%+ for fly.

If you want to get fussy, pH measure a cool sample of the mash and adjust to 5.2-5.5.

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Permalink Reply by Crusader-Rob on February 7, 2014 at 4:32pm

Are you sure those figures are correct? Everywhere I read suggests BIAB  has a lower efficiency, and my brews tend to agree with that.

I normally mash 60-90 mins, I'm doing alot more at 90 mins these days, for full conversion of lower temp mashes.

Get my crush from finneys, which has been pretty reliable for around 68-70% ost of the time.

Once the mash is set I stir rigorously, to ensure an evenish temp.

Is it worth using that 5.2 stabiliser for awhile to set my ph scorrectly, and correct the water volume amounts to get right on the money for lt into fermenter ,which will give me a more accurate idea of what sort of efficiency i get. Which will subequently change slightly when i finally sort a pump out for re-circ.

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Permalink Reply by Grant R Baker on February 7, 2014 at 5:17pm

I think you might be right... I can't find the article and other sources suggest BIAB is lower than Batch.

BIAB brews should be double crushed (I do on my small BIAB batches) but the downside of that is higher protein in the boil.

Your mash times are pretty good... 60minutes is my minimum, plus I do a 20-30minute batch sparge.

Do you keep any water reserved to wash the grains after the BIAB mash, help get a little extra sugar from the grains.

5.2 stabiliser has a rep for adding a salty taste to certain waters and like any chemical you should only use it if you need it.

A $15 pH meter from Trademe & Gypsum is all I use now... and only if the mash needs it... which is not often (Welly water is pretty good)... but some grains seem to create different conditions (pH wise) in the mash. (example... Gladfields Pale Ale seems to have a high pH, but when other grains are added it all settles down).

All in all I find worrying about pH a bit fussy... if you can get a stable efficiency then adjusting the grain bill to match might be the simplest option... set yer Beersmith to 70% thus yer targets will adjust, easy to compensate.

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Permalink Reply by Crusader-Rob on February 8, 2014 at 9:48am

Yeah I've heard the 5.2 is like that. I've set to 70% and normally miss by maybe 1-2 points but 5 was a bit much.
I need to play with my water volumes, to establish a good volume to set. I normally go with what's in my head. For volumes. And hit closely. Sit with it in half litre increments.
I looked at my recipe last night and a couple of my grains are too high in points. Saying melanoidin is 1.036 potential is wrong in my experience. So I need to work on that too.
Adjusting my efficiency to 68 and try adjust from there.

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Permalink Reply by Druid on February 8, 2014 at 12:08pm

"what are the different ways to improve total brewhouse efficiency. Bare in mind I hit a good mash efficiency. and missed target pre boil OG by 2 points."

"Yesterdays Belgian IPA I aimed for 1.063 and 21 litres into the fermenter, but got just under 22 and 1.057, a considerable difference"

There are 2 separate issues at play here:

1. Based on your comment, if you missed your final gravity by 6 points and yet you only lost 2 points when you measured your boil gravity then the only other way to *not* hit your target gravity (regardless of final volume) is if you didn't boil off as much as your recipe thought you would.
Have you measured how many liters you actually boil off during a 60 minute and 90 minute session using your normal boil and used that figure in your equipment profile?
If you don't have an accurately calibrated sight tube on your kettle to measure volume, you could do what I did and marked calibrated steps on my mash paddle handle and used it as a dipstick during the boil to get accurate volume readings.
Based on logic alone, it can only be an inadequate boil off compared to the Beersmith prediction *or* you are not getting accurate gravity readings ie. calibration issues, you use a hydrometer and your wort was not chilled to near 20*C *and* adjusted for any difference between temp and 20*C.

2. Not hitting final volumes is another separate but related issue and is based solely on volume out of the mash tun less your process losses ie. boil off (which sounds like it's being underestimated anyway, meaning you should get more volume into the fermenter, not less), loss to trub, wort you couldn't transfer out of the kettle, spills etc.
It sounds like you need to measure how much you lose at each step and then compare them to the various equipment loss settings in Beer smith.

(EDIT) just reread you post and noticed that you exceeded your final volume - 1 litre in 21 is pretty close to 5% which is pretty close to the actual loss in gravity during the boil - so it sounds like your boil off (or lack of) may account for some (most?) of the variation.

FWIW, I wouldn't bother worrying about mash pH yet - the variances are probably too large to be explained by it. Just my 2c worth...

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Permalink Reply by Druid on February 8, 2014 at 1:27pm

There is another possibility for the discrepancy you are seeing in your pre and post boil gravities:  I've found what I believe to be a bug in Beersmith's gravity calculations between start and and end of boil.

To demonstrate it, we need to use the total gravity points rule:

Pre Boil Gravity Points x Pre Boil Volume must equal Post Boil Gravity Points x Post Boil Volume

(Note that the gravity points are calculated by subtracting 1 from the gravity them multiplying it by 1000 ie. 1.055 -> 55)

We can express that as:

Est BGPoints x Est preboil Vol = Est OGPoints x Est postboil Vol

This is another way of saying that regardless of how hard and how much you boil off, you can never change the total amount of sugar in the wort.

We can rearrange this to allow us to predict what the final gravity should be if we predict a particular post boil volume:

Est BGPoints x Est preboil Vol

-----------------------------------------      =     Est OGPoints

       Est postboil Vol

So, lets take this rule and check it against what Beersmith predicts.  Note that we are using Beersmith's estimated figures, not actual.

If we look at the first screenshot, you will see that:

Est BG = 1.053 -> 53 BGPoints, 

Est pre boil vol = 33.79 litres (grayed out at top of image) 

and 

Est post boil vol = 27.04 (7th field up at bottom right).

Based on these figures, Beersmith estimates that our Est Original Gravity will be 1.069 (middle right)

So, to check using the total gravity points rule we get

53 x 33.79

-----------------   = 66.23 (or OG = 1.066)

     27.04

What?  That's a full 3 points out on Beersmith's estimate of 1.069.  That's equivalent to approx 5% less sugar in your wort if you followed this recipe.

When I first discovered this, I was a bit disillusioned as I find Beersmith indispensable. 

So, in the interest of salvaging it in my eyes by increasing it's accuracy, I looked at all the settings in Beersmith and discovered that if I changed the Cooling Shrinkage from 4% to 0% in the Equipment profile, I got much more accurate figures:

So, with Cooling Shrinkage set to 0% (2nd field up, left hand side), Beersmith now estimates the following:

Est BG = 1.055 -> 55 BGPoints, 

Est pre boil vol = 32.75 litres (grayed out at top of image) 

and 

Est post boil vol = 26.00 (7th field up at bottom right).

Based on these figures, Beersmoth estimates that our Est Original Gravity will be 1.069 (middle right)

So, to check using the total gravity points rule we get

55 x 32.75

-----------------   = 69.27 (or OG = 1.069)

     26

Much more in line with what we're expecting.

So, I now no longer use the 4% cooling shrinkage and have set it to 0%.  To compensate for the smaller resultant volume as a result of not taking cooling shrinkage into account, I bump my batch volumes up from 21 to 23 litres and end up with enough to fill 21 - 22 litres.

I'm not 100% sure whether the calculation for shrinkage is at fault here or just that the magnitude of the adjustment from 4% to 0% is enough to compensate for an error elsewhere.  

I'd still be inclined to make sure all my volume and gravity measurements are calibrated. But if you are seeing variation between your predicted gravity after the boil *and* you are certain hit your pre boil gravity, check out this adjustment to see if it brings more accuracy to your brew day.

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Permalink Reply by Paul Finney on February 8, 2014 at 1:51pm

HI Rob, just using the boil off tool on Beersmith, but if you had boiled off one more litre you would have been around 1.060

So only 3 points off. And then if you possibly read that reading at even 24 that gives you another point...

When doing higher gravity beers in BIAB the efficiency suffers. It may be worth keeping track of the gravities v the amount of grain you are using to see if there is a pattern, and therefore you can reduce your efficiency of the recipe to compensate.

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Permalink Reply by Crusader-Rob on February 24, 2014 at 10:00am

I brewed up a storm on the weekend.....Haha, for those chch people, They'll understand.

I mash in for a 1.066 black ipa, first time brewing this beer. which was going to make life a little interesting for final volumes and corrections on my water voluimes etc. etc.

mash efficiency was dead on, as pre-boil was estimated at 1.054, and i hit 1.054, then heres where i hit the snag. I boiled for 60 mins and ended with 20.5litres of very black wort in the fermenter. The OG was only a mere 1.062, so i missed the OG by 4 points again. 8 points in 1 hours boil. would this be acceptable? and total efficiency around 63-64%.

Efficiencies need adjusting, but I'm thinking for my next beer i need to get my grain double mill, to try and up my efficiency, what are the draw backs on this? I'll be getting  a mill hopefully mid year this year.

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Permalink Reply by Paul Finney on February 24, 2014 at 10:58am

Hi Rob, sounds like the calcs for your boiling may be off? In both of your examples you've hit, or close to hitting, your pre boil gravity but are then off for OG. In your first example you missed pre boil by 2, and was out by 6 for OG. In this example you were bang on for pre boil and 4 off for OG. So at least you are being consistent!

Do you use beersmith? Have you gone through and adjusted your set up?

What volume of wort should you have going into the fermenter?

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