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Brewhouse Eff. higher than Mash Eff. ??

Wingeezer

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When plugging volumes and SG figures into Beersmith for a particular batch, I often seem to get results indicating that my Brehwhouse Efficiency is higher than my Mash efficiency.

If my understanding of the definition of these terms is correct, I think this is an impossibility!

I would think that the only reason I am getting this is errors in my measurements of volume and/or SG.  Is there any other explanation?

Strangely though,  I don't get this reversal on every batch.

I think if my my volume measurements  were incorrect (I use a calibrated dipstick in my kettle and paint markings I put on my carboys by adding water one liter at a time and  painting the marks.)    then I would have the same issue on every batch.

I do use a refractometer for my gravity readings but they seem very repeatable,  and any time I have cross checked readings with an hydrometer they have been right on.

Anyone else ever experience this sort of relationship and/or have any advice or comment?  Am I missing something here in thinking that
Brewhouse Eff always has to be less than Mash Eff.?

Brian ...... confused!









 
You are on the right trail in looking at the pre-boil and post-boil numbers.  One way to check to see if these numbers are correct is to do a gravity point balance, comparing the sugar content before and after the boil, as this amount will not change (barring any boil additions of simple sugars, fruits, etc.).

To do this, you must correct your volume measurements to room temperature on the pre-boil measurements.  If you are using 4% (default setting) as the expansion factor in BeerSmith, use this number to adjust the hot side volume measurements.

You also need to remember to add in any volume losses and account for any top off water added.

Take your gravity readings pre- and post- boil and convert them into 'points' by subtracting 1 and multiplying by 1000.  Thus a gravity reading of 1.043 becomes 43 points [(1.043 - 1) * 1000]

Now correct your hot side volume measurements (basically pre-boil volume) through use of the thermal expansion factor (I'll assume that it is 4% for this example).  Thus a pre-boil volume of 22.40 liters is corrected to room temperature as 22.40/(1+4%) = 22.40/1.04 = 21.54 liters

Your cold side volume is made up as [volume to fermentor] + [trub and chiller loss]

Now the balance looks like this:  pre-boil volume (corrected) * pre-boil gravity points = post boil volume * post boil gravity points.

If this is off by more than 1% or 2% then you have an error in your measurements somewhere.

Note that if you add top off water to the fermentor, your readings on volume and gravity must be taken before you add any of the water.

The only other time you can see Brewhouse efficiency exceed the mash efficiency is with the addition of a significant amount of sugars at the end of the boil.  BeerSmith does not do a good job at accounting for this type of addition when calculating BHE.
 
Many thanks, I will try what you suggest in order to investigate further to see where I am messing up here!

No extra sugars added in the latest batch I made just yesterday - that again seemed to give a Brewhouse Eff higher than mash eff when I plugged the numbers into Beersmith2. 

In fact it was the simplest recipe I have ever tried!  Just 2 row and cascade,  in an attempt at a
New Albion Pale Ale clone!

Brian.



 
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