Author Topic: Brewhouse efficiency/mash efficiency dialling in  (Read 529 times)

Offline brian_muz

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Brewhouse efficiency/mash efficiency dialling in
« on: June 15, 2019, 07:57:00 PM »
Hi all,

I need some help dialling in my brewhouse efficiency and mash efficiency. I understand that in BeerSmith 3 you set the brewhouse efficiency and the software calculate the mash efficiency based on this. However, for my last three brews the brewhouse efficiency was been bang on but I'm getting significantly better mash efficiency than BS3 predicted. Is there a way to dial this in?

My last brew was

Estimated BH efficiency 60%
Actual BH efficiency 59.8

Estimated mash efficiency 66.3%
Measured mash efficiency 76.1%

I've taken a screen shot in case it helps (attached).

Offline Oginme

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Re: Brewhouse efficiency/mash efficiency dialling in
« Reply #1 on: June 16, 2019, 05:00:30 AM »
The screen shot really does not give us the information needed to help you out.  We can give a lot more direct assistance if you export the recipe as a .bsmx file and post it as an attachment here.

Meanwhile, your volume to fermenter is higher than your target, which may be an indicator that your volume balance is off.  Efficiency, both mash and total, is a factor of both gravity and volume.  Knowing your starting water volume, pre-boil volume, and post boil volume in comparison to the targets would give you the information you need to resolve the balance and get the model in line with your actual process.

Recycle your grains, feed them to a goat!

Offline brian_muz

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Re: Brewhouse efficiency/mash efficiency dialling in
« Reply #2 on: June 25, 2019, 04:10:07 AM »
OK, I've attached the .bsmx file.

The measured batch size was greater than estimated as I usually lose 1.8L to the dead space in the boil kettle but I drained 1.5 litres of this as a bit of an experiment into kettle trub.

Offline Oginme

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Re: Brewhouse efficiency/mash efficiency dialling in
« Reply #3 on: June 25, 2019, 05:53:46 AM »
Your comments give more clarity.  You have changed your process by now draining more wort from your boil kettle which alters the brew house efficiency (BHE). 

The way BeerSmith calculates BHE is by comparing the percentage of sugars which make it to the fermenter as compared to the potential amount of sugar available in the fermentables bill you provide.

What I see in looking at your sessions tab is that you hit your gravity target from the mash, but ended up with a greater volume than anticipated by about 3.6 liters.  This gave you a higher mash efficiency since you now recovered more sugar from the grains than was calculated from your equipment profile.

Next, you ended up with 21.5 liters in your carboy, but with a lower gravity than target.  This added volume compensated for the lower gravity to give the same amount of sugar as your equipment profile predicted.  Thus the same brew house efficiency.

Now, from your figures you should have the same amount of sugar points pre-boil as post boil.  If I look at the figures, you have 29 l * 54 gravity points =  1566 sugar points.  Post boil you have [21.5 l + 2 l (trub)] * 60 gravity points = 1410 sugar points.  This deficit in sugar post boil from the pre-boil amount indicates that there is a measurement which is not correct.  Either your post boil gravity measurement is off, you have more loss to trub than you counted on, or your pre boil volume measurement is off.  You need to track this down before you make a change to your equipment profile.

If you back calculate your pre-boil volume from the ending sugar points, you get a pre boil measured volume of 26.1 L which is closer to your target value.

You will also need to address your boil off rate, since it is most likely set too high.  If you started with 29 L and boiled down to 23.5 L, your boil off rate would have been 5.5 lph instead of the 3.5 lph in your equipment profile.  If instead you actually yielded 26.1 L post boil, your boil off rate would have been 2.6 lph which is below the value in your equipment profile.

My recommendation would be to keep your profile where you had it for another brew.  Make careful measurements and compare the values to see how much error there may be in your measurements.  If you are relying on pre-stamped volumes in your boil kettle or mash tun for measuring starting water or wort, check those volumes against a measured amount of water added.  I have seen pre-stamped volumes be off by as much as 0.6 liters due to variables in manufacturing or poor alignment of the engraving device.
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Offline brian_muz

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Re: Brewhouse efficiency/mash efficiency dialling in
« Reply #4 on: June 27, 2019, 06:41:42 AM »
Wow. Thanks for the detailed reply and for taking the time to analyse me file. I can't believe a stranger from (no idea where you're from. I assume everyone is American... too much TV) would put so much effort in.

I think you've arrived at the conclusion I did. Something isn't right. I just assumed it was a mash efficiency thing because for the last two brews I've been super careful of my measurements. I've made sure the markings in my boil kettle and fermenter line up and outside of BeerSmith (in excel) I've tracked volume and gravity at every point I could think of. I even calibrated my refractometer to make sure that wasn't the problem.

The only things that confuse me are volumes at various temperatures. The boil kettle volumes I take can be at different temps. I know this can make a small difference. Something is out though.

I'll take your advice and do another brew with the same setting. I'll report back in a few weeks.

Thanks again for your help. I really appreciate the effort.

Offline Oginme

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Re: Brewhouse efficiency/mash efficiency dialling in
« Reply #5 on: June 27, 2019, 07:01:04 AM »
Brian,

Just glad to help out in any way I can.  Yes, I am American though I admittedly watch very little TV.  Too much to do in life to spend time in front of a screen watching others pretend to do things in life.

The volumes can be confusing in BeerSmith.  The easiest way to track them is on the 'volumes' tab.  BeerSmith applies the thermal expansion coefficient as a constant for any volume above ambient temperature.  So when you measure in your water, the target volume is actually at the hot water temperature.  You can follow this on the volumes tab in your recipe to see where the thermal expansion is applied and where it is subtracted.
Recycle your grains, feed them to a goat!

Offline dtapke

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Re: Brewhouse efficiency/mash efficiency dialling in
« Reply #6 on: June 27, 2019, 09:17:18 AM »

My recommendation would be to keep your profile where you had it for another brew.  Make careful measurements and compare the values to see how much error there may be in your measurements.  If you are relying on pre-stamped volumes in your boil kettle or mash tun for measuring starting water or wort, check those volumes against a measured amount of water added.  I have seen pre-stamped volumes be off by as much as 0.6 liters due to variables in manufacturing or poor alignment of the engraving device.

I have to second this. It seems as though there's a process issue you may be dealing with. Have you ever run a batch through with just water to measure your losses? Also, when you're taking gravity readings are you mixing the wort thoroughly to reduce the chances that you're sampling from stratified layers of wort?

It can be difficult to determine the source of many issues via the internet, I would start by either trying to replicate the last brew, or do a test run with water to make sure your measurements are accurate. My "30g" SSBrewtech kettles are off by 2L in one spot, then back on at another. So definitely check your volumes to make sure they're accurate.
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