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Volume losses and low efficiency


New Forum Member
Mar 21, 2019
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Hey all! New to the forum, but have been using BeerSmith since I started brewing in January of 2018. I'm currently on Batch #11 I think. Here is my brewing setup:

Igloo 10gal mash tun with AIH false bottom, 15gal boil keggle with NorCal false bottom and whirpool arm, chugger pump w/ hoses/camlocks, 1/2" x 50ft immersion chiller, Hellfire burner

A friend of mine set up the equipment profile in BeerSmith since he used to have the same setup. I currently pre heat the igloo tun using ~120F hot water heater water, heat up strike water then dough in. It took me a while to get my temp losses sorted out, but I have that under control at this point. Mash profile is always single infusion batch sparge. Batch size is 5.5 gal for corny kegs.

Most of the batches that I have done have had low pre boil volumes. I noticed one day that when you open/print the 'Brew Steps' section, it says to add top up water, despite having that unchecked in the software profile. That could account for my volume losses, but at the same time, my ABV and numbers would be different correct? To achieve ~6 gal into the fermentor I'd assume I'd need ~7-7.5gal pre boil.

In the research that I have done I've seen a few topics that have noted to ensure the mash profile has the proper water to grain ratio....typically 1.25 qt/lb. I will check that when I get home.

Something, or multiple things are wrong, and I am going nuts trying to figure it out. Any help is appreciated. Cheers!


Grandmaster Brewer
Mar 16, 2013
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New Hampshire, US
While you received the equipment settings (and I am guessing the brewhouse efficiency) from someone who had the same set up, this only helps is seeing what someone else's equipment gave them for settings.  You really need to measure the various parameters to make sure your system is representative of the settings you have in the profile.  Everything you have listed so far points to poor definition of your losses in the equipment profile.

You can step through and measure the dead space in your cooler by adding a known amount of water to above the drain line and then measuring the amount which can be drained out.  Boil off rate can be calculated from the pre boil volume and post boil volume. Some brewers do a quick boil of just water to give themselves a good starting number.  Likewise, taking a known amount of water and draining it from your boil kettle will help define your loss to trub and chilling.

If your equipment has volumetric markings, I would highly advise double checking them and creating your own measuring stick for each piece of equipment where you will be taking volume readings.  The factory markings are based upon engineering plans and not actual construction. 

Once you know your volume losses in your cooler mash tun, you can determine the grain absorption rate by taking the water in less the wort out to get your total water loss.  Subtract the dead space measurement from that figure and divide by the weight of grain added will produce the amount of water which was absorbed by the grains.  This figure can be updated in the program by clicking on 'options' > 'advanced' > grain absorption.  There are two figures, one for standard set up and one for BIAB.  You can ignore the BIAB setting and just update the standard absorption coefficient.

You did not mention anything about your gravity readings.  To determine if you have low efficiency, you need to make sure you factor in gravity readings AND volume readings.  Entering these into the 'session' tab in your recipe on BeerSmith will enable to program to calculate your actual mash and brew house efficiency.  You can take these numbers and feed them back into the equipment profile to further dial it in.

There are some videos on YouTube which will walk you through these measurements and how to put them into BeerSmith and you can find them by searching for 'BeerSmith' and 'equipment profile'.

P.S. the brew sheet has a fixed line in it before the boil and after the boil to 'add water to achieve volume of xxx' as a standard feature.  It does not mean that you have add water or will need to, it is just to remind the brewer that the option is available.


Grandmaster Brewer
Nov 5, 2018
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Portage, Wisconsin
Yeah... take that profile, and throw it in the trash. Then make your own.

As oginme stated, there's plenty of tutorials including ones on the beersmith page. doing a test run with water is a great way to get a super accurate profile.

as far as efficiency, are you talking brewhouse efficiency or mash efficiency? as both are somewhat related, but one is mostly profile related and one is more process related.