Brewhouse effeciency

[ScottV]

With the rising cost of raw materials I started doing a few calculations to find my brewhouse effeciency, something i should have done a long time ago.

what i found does not make me happy.

I calculated that i am only getting 70% efficiency.

I have a 20bbl single infusion mash/lauter combo. the vessel has an ID of 75" and my usual grain bed depth is around 20 - 25" deep.

I am using around 1300# of malt to knock out 21.5bbl of 13P wort.

the thing that bothers me most is that my last runnings are consistantly above 5P, sometimes around 7P.

I am just looking for someone to either....

a. tell me i am doing something very wrong and i need to look at everything from my raw materials to my technique.

b. tell me that 70% effeciency sounds about right and elevated last runnings can be expected with a small brewhouse.


thanks for any help or advice,


Scott

[Buckley]

there are some variables here.
A. What is your average run off time
B. Do you mill your own grains
C. what are the stats on you your latest order of grain

[ScottV]

Average runoff time is 1hr 10 minutes

we mill our own grain on a 2 roll mill, visually checked each run to make sure there are no whole kernels.

I dont have the malt numbers in front of me right now, i will get them, but the previous lot numbers had a %extract, CG, as-is, of 77%

[Wes]

Scott, you are indeed in the 70% efficiency territory. If your final runnings are 5+ºP then I suspect that your runoff may be a little to aggressive. We would normally be looking at a 2 hour runoff for a single infusion system such as you describe. But this will be dependent on a host of variables like crush, brewing liquor profile & pH and of course the malt itself.

As a general rule of thumb we target efficiencies of 87 to 90% for these types of systems when setting them up. For your 21.5BBL (25HL) brew length, we would use 990 - 1030# (450 - 470kg) of malt. That sits about 87 to 90% efficiency. First runnings should be around 19 to 20ºP and final runnings around 1.5 - 2ºP.

Have you checked the layering in your spent grist as you open the manway? What about an iodine test on the spent grist?

Wes

[Wes]

Average runoff time is 1hr 10 minutes

we mill our own grain on a 2 roll mill, visually checked each run to make sure there are no whole kernels.

I dont have the malt numbers in front of me right now, i will get them, but the previous lot numbers had a %extract, CG, as-is, of 77%

Our posts crossed - what type of 2 roll mill?

Wes

[ScottV]

We have an adjustable 2hp, 2-roll mill. I can adjust the gap as well as the tension on the floating roller. I check my grist to make sure there are no whole kernels, and that the malt is not turned to dust. On my next brew i will adjust the gap to get a finer crush and will slow down the run off.

Scott

[Wes]

Some of the 2 roll mills we have seen with smooth rollers can be very difficult to get the right compromise - especially if your malt is very friable. You mention a "floating roller". Are not both rollers driven?

Wes

[Brett0424]

It sounds to me like you're just leaving too many sugars behind. Sparge slower I'd say.

[ScottV]

I have heard from a few freinds and they all seem to think that i am lautering way to quickly. I will slow it down and see what happens. Looking back at our brew logs it seems that recently the times have been a lot shorter than what they were 6 months ago. We have gone from a 90 minute runoff to a 60-70 minute runoff.

I will report back next week. If anyone has any other suggestions i would love to hear them.


thanks for all the help,

Scott

[Brett0424]

Good luck, my other suggestion would be to keep an eye on your ph if you're not already.

[BrewinLou]

Just checking for whole kernels is not a good way to judge. We just broke down our mill and reset it. When we set it back up what looked like a good grist to me was a long way off from what the US Standard Sieves read. We had to adjust it several times. Just one part of the whole.

[youngbuckbrewer]

I have had this same problem with efficiency in the past. At another brewery I was working at we would lauter in about 60-70 mins, and as we slowed down the lauter even 10-20 mins the extract efficiency went up significantly. The wort will take the path of least resistance in the mash bed, so running off to quickly can cause the wort to miss flowing through the majority of the filter, thus reducing your extract and efficiency. We get around 83-85% depending upon the grist and it all came from being a little more patient in lautering. Watch the potential to oversparge also.



Michael Uhrich
Carter's Brewing
Billings, Mont.

[Wes]

Another point to note is the habit of equipment manufacturers to place more outlets on the bottom of the mash tun than are needed. This unfortunately encourages faster runoffs. The design rule is typically 1 outlet per m² (11 ft²). We frequently see double that on some makes of kit.

We always start the runoff very slow then gradually increase the flow as lautering proceeds. But we always aim for around 2 hours - longer is OK, less is not. Like so many other things in brewing, you need to have a "calibration point" as to where you want to be - before you start.

Wes

[ScottV]

Where can i buy a set of sieves to check my grist with?

Scott

[grs]

Ditto to ScottV on the purchase of sieves.

Also, is there any merit to checking the mill gap with a set of feeler gauges and maintaining/opening/closing the gap with the variation in kernel size? I see a lot of people here talking about mill gaps and I have yet to find a thread where anyone mentions actually measuring the gap. Is it just not done? No point to it?

[BrewinLou]

I seemed to find a good number of suppliers using google. This one looked pretty good but ours are 12" diameter not 3".

http://www.akmining.com/cart/tyler.htm

Malting and Brewing Science lists grist % info for these screens

10
14
18
30
60
100

[Wes]

Ditto to ScottV on the purchase of sieves.

Also, is there any merit to checking the mill gap with a set of feeler gauges and maintaining/opening/closing the gap with the variation in kernel size? I see a lot of people here talking about mill gaps and I have yet to find a thread where anyone mentions actually measuring the gap. Is it just not done? No point to it?

Again, so many variables. Using a gauge as a starting point is fine, but then you will need different settings depending if your rollers are smooth, grooved or diagonally slotted. The mill construction and bearing housings come into play - do the rollers deflect under load (like hard wheat malt), what was the barley season like etc etc.

We recommend using an old hacksaw blade with the teeth ground off as a gauge to start with (1/32" or 0.8mm in thickness) but then you must check the result. And keep checking! Wheat malt will always need to be a little finer in crush than barley malt. Plump English grains will need a wider setting than domestic pale malts. And raw wheat can sometimes be like crushing small ball bearings - at least here in Aus.

Wes

[MatthewS]

I just got a full set of 6 sieves from McMaster Carr... not seap but worth every penny to get the right grist.

[lhall]

One trick I learned a while ago, is to check the mill gap setting "under load". Take some soft plumbing solder and run it through the mill with a lb or two of grain. The grain will force the rollers out against their bearings, and the solder will get compressed down to the mill gap setting. Measure the thickness of the solder with a pair of calipers and you've got your mill gap "under load".

[scmorgan]

A common mistake is to assume you will get better efficiency from milling finer. Most likely is the case you can decrease efficiency if you are running an infusion tun with a deep bed.

Ingrained in me by my former Bass IBD Diploma Master brewer is a courser crush with a deep bed to enable the mash to 'float' and slow slow run off's. I can send you the schedule we run if you like.

Leave fine crushes and fast run offs to those brewers with a system akin to a Steinecker or mash filters...

Scotty

[Sir Brewsalot]

Well, I tend to run my milling at the edge of a what will give me a stuck mash... I'm sure there's a point of diminishing return here with too fine a milling (channeling and the like), but this is something I discovered a while back when I switched grain suppliers.

I milled in with the setting from the old grain, was SHOCKED to see how fine it was. Set my worries aside and brewed with it anyway, and was amazed at the efficiency boost I saw.

Between the change in malt and the efficiency boost, I've been able to pull a couple sacks of base malt out of the grain bill - that's real money!

Cheers,
Scott

[scmorgan]

Its all about what works best for your system in most regards - find out whats best and keep doing it!

[Sir Brewsalot]

Agreed! And here's another example of what I was told never to do:

I sparge with 190F water to get the grain bed up to 180F (as my thermometer reads it) to lower the viscosity. No astringency issues so far - even with the more "delicate" styles.

Your experience may be completely different on your system.

Cheers,
S

[beertje46]

I just got a full set of 6 sieves from McMaster Carr... not seap but worth every penny to get the right grist.

McMaster-Carr (http://www.mcmaster.com/) page 365. We use the brass/brass 12" model in the increments Brewinlou listed above. With the cover and bottom the set will set you back $622.06. Not cheap but the increase in efficiency will pay for the set quickly, give you cleaner sweet liquor and (hopefully) less headaches in your lauter. Buy some today!

[jason.koehler]

Agreed! And here's another example of what I was told never to do:

I sparge with 190F water to get the grain bed up to 180F (as my thermometer reads it) to lower the viscosity. No astringency issues so far - even with the more "delicate" styles.

Your experience may be completely different on your system.

Cheers,
S

Did you happen to check the PH?

Due to a flub a few weeks ago, the bottom of our kettle was left open while we were adding water to our HLT and about 700 liters of water ended up in the kettle. We used the wort/water mix in the kettle, which we had already begun heating to a boil and was over suggested sparging temps, to sparge the grains again because of course we were WAY under target gravity. We ended up pretty close to expected OG, but have been worried about astringency...we'll be moving it to to a secondary on Saturday so we can check it then...keeping my fingers crossed!

[Sir Brewsalot]

Nice solution to what could have been a heartbreaking problem... I made the same mistake once about 2 years ago, though managed to catch it pretty quickly. Since then I'm pretty OCD about checking all valves before turning on the HLT pump. Funny how that moment of terror stays with you.

I monitor my pH pretty closely. I've seen tap water here come in as high as 8.8 (8-8.4 is the norm), which to me seems ridiculously high - but I always scoop some out for the morning coffee before acidifying.

Cheers,
S

[Moonlight]

While milling yesterday I noticed a bag of malt that had picked up a little moisture. Not hugely so, but enough that it would change its friability in the mill. This could affect performance in wet weather. Imagine that a damp cracker doesn't shatter as nicely as a dry one.

[ScottV]

I brewed a standard batch today with the following adjustments

Fine tuned mill to create a much finer grist, much smaller pieces of malt, no whole kernels. I think i can afford to mill it finer wth out a stuck mash

Increased the sparge temp to 185F, the grain bed temp never went above 176F

Increased runoff time to 1hr 40 minutes from 60 - 70 minutes

Mashed in with a ratio of 1qt / # malt, 1320# = 330gallons h20

First runnings where 19P, which seems low

ran off about 2.5 bbl before starting the sparge.

Maintained a fairly wet grain bed, with water covering most of the surface.

ran off at about 7 gallons per minute.

last runnings where around 5.5P and the kettle gravity was lower than it should be.

I am not sure what else to do but i will keep playing with this

thank you to everyone for all your suggestion, I will keep trying to figure this out and let you know if i come to a conclusion...

Scott

[Sir Brewsalot]

You may be able to go a little hotter if the grain bed isn't passing 180F. That's the ceiling I use, but the difference is bound to be minor.

Also, if it's of any use, I like to keep an inch of water atop the grain bed, so that it still has some float... again, using this technique in conjunction with a super fine milling to prevent a stuck mash/channeling in the bed.

Did you already say what your water pH is?

[ScottV]

The last I checked it was in the range of 6.5 - 7.

The pH of the mash was is usually 5.4

how much of your wort do you run off before you start to sparge?

Scott

[Jephro]

You may be able to go a little hotter if the grain bed isn't passing 180F.
What is the importance of bringing the mash temp up this high? I usually sparge with 170-172 water. I runoff pretty slowly and get great efficiency. Is the high sparge temp this a viscosity thing?

[Sir Brewsalot]

Yes, my thinking is that it lowers the viscosity of the sugars and improves their physical extraction. I start hot (190F) and dial down as the grain bed temp rises... with a goal of reaching and holding 180F... but again, this is just what I've found works for my system/grain/insert-other-variable-here.

And the 180 ceiling may be an arbitrary one.

S

[Moonlight]

How did the wort taste? Did the lauter bed get stiff enough to stand a paddle up in?
I'm thinking if the thermometers weren't calibrated, it could cause this. Was the last pH check from before these problems? I know rainfall really changes my water chemistry...don't have the snow thing here.

I am curious if it is now cost effective for brewers to add rice hulls to the mash and mill the malt much finer. I would guess that the rice hulls are cheaper than the loss of malt extract caused by milling coarse enough to be lauterable.

[FrankM]

Congratulations to Valley Brewing.

On their first trial batch on a new 30 bbl system, the brewhouse efficiency rate is 93%.

http://valleybrew.blogspot.com/

[big_al]

wow! 93% effeciency.

reading this post has got me a bit worried. Either I am misunderstanding your calculations of effeciency or my brewery is very ineffecient!.

At the moment, when I calculate my grain bill, I include factors for extract from the grain and brewhouse effeciency.

for example, say I wanted to make 750 litres of 11.5P wort from pale malt

750 litres x 120g sugar per litre = 86,250g sugar = 86.25kg sugar required
allowing only 80% extract from malt = 107.8kg
allowing only 80% brewhouse effec. = 135 kg total malt added to mash tun

from what everyone is saying, sounds like this is very ineffecient?

In reality, I have been using 120kg malt to end up with 720 litres of 11.5P wort

working backwards, this means I am working at only about 69-70%.

should I be worried?

Allan

[Wes]

Hi Allan, different method of calculation I think. Your figures come out at 86% for the 750ltr/135kg brew and 93% for the 720ltr/120kg brew when run through Promash (which we use for all our recipe/performance tests).

I think you are doing your calcs by the traditional German method based on sugar equivalent. Bottom line - dont worry, you are right in the ball park for a small micro.

Wes

[big_al]

thanks Wes,

I went back to my calcs and worked out just the brewhouse effeciency component using a malt extract of approx 80% and came to the same conclusion.
I can sleep now...in between mash outs!

Allan

PS see you in Melbourne?