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Setting up losses for correct water levels with BIAB


Oct 6, 2016
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So I've got my equipment profile fairly well set up but I tried to adjust some keggle losses and ended up with a terribly low OG.

I BIAB and my first 5 gal brew based on BeerSmith and had a loss to trub and chiller of 0.5 gal.  My keggle has the ball valve a little higher up and I figured my loss to be closer to 2 gal.  I adjusted the trub/chiller losses to 2.00 gal and on the direction of BS, my increased water levels ended up leaving me with an OG of 1.030 rather than 1.056.

Because I'm doing BIAB, do I count that 2 gallon loss left over in the keggle after the boil as Mash Tun losses to keep my grain/water ratio correct because it was obviously off when adjusting it for losses in trub/chiller section.


Grandmaster Brewer
Mar 16, 2013
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New Hampshire, US
Put some water in your keggle, enough to cover the drain valve and then open it up and allow as much water to drain out as possible.  Close the valve and pour out the remaining water into a bucket and measure what is left.  Now, do you tip the keggle when you drain?  If so, then repeat above and tip the keggle as you normally would.  Now measure what is left.  That number is your trub loss.  Adjust your equipment profile with this loss

Since you are doing BIAB (I am assuming full volume), you don't worry about water to grain ratio. All your water will go in up front.

Next, look at your last recipe brewed and find the actual mash efficiency calculated by BeerSmith (not the estimated).  Copy the recipe and rename the copy as "actual" or something which distinguishes it from your original.  Open this file up, change the equipment profile to reflect your new wort losses and make adjustments to the "BH efficiency" until your estimated mash efficiency matches the mash efficiency that you actually attained when you brewed the recipe.

Now reopen your equipment profile and enter this BH efficiency into the mash profile.  Save the file and use this for your next brew.  Repeat this a couple of times and beersmith will get better at predicting what you will actually achieve.