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]

mash effeciency

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]

mill type

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]

lautering time

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.

[Guest]

Lauter times

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]

standard seive

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?