Author Topic: calculating OG (Or sugars lost in trub)  (Read 3883 times)

Offline Jake Fegely

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calculating OG (Or sugars lost in trub)
« on: February 29, 2012, 06:07:42 PM »
I've used BeerSmith 1.4 for about 20 brews and have it pretty well dialed in, with one exception. It will accurately predict my beginning gravity and volume. It will accurately predict my after-boil volume. However my OG is usually less than expected. I believe this is caused by the fact that the Equipment setting for trub and chiller loss calculates water loss only. In my mind at least, it should reduce the total sugars.

I've read this same question on HBT and BeerSmith forums. The answers I've read seem to fall into 2 areas. To test those responses, I took the results from my last brew and modified Beersmith to see if I could get BeerSmith to correctly calculate 4 key numbers - Beginning gravity and volume, and OG and volume.

Under my current use of BeerSmith I can correctly calculate 3 of the 4 numbers - everything except OG.

The first response to "correct/get around" this issue is to increase batch size. When I changed this on my last recipe, it dropped my BG to below actual and kicked BG volume above actual. Now only 2 of 4 numbers are correct.

The second response is to adjust brewhouse efficiency. I adjusted efficiency so that it predicted my actual OG. In that case both volumes were also correct, but my BG was again too low.

The only thing I can think of is to look at the recipe 2 ways. First, exactly as I currently do, so I know what BG and volume to expect. Then change the brewhouse efficiency (by a varying amount based on amount and type of hops). That will provide the correct OG.

Seems like a clumsy way to formulate a recipe. What am I missing?

Does BeerSmith 2.0 address this?


Offline acacko

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Re: calculating OG (Or sugars lost in trub)
« Reply #1 on: January 18, 2013, 06:17:17 AM »
I'm having a similar problem.
I have my trub loss set at 1 gal from the boil pot and .5 gal in the fermenter.
I consistently miss my gravities. What I tried is using the water volumes from the
original receipe size but scaling the reciepe up by 1.5 gals for my grain and hops.
This method seems to work very well, and I've been within 3% of most receipe's specs.
Problem is, it seems like I'm not using the software correctly

any thoughts?

Offline mm658

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Re: calculating OG (Or sugars lost in trub)
« Reply #2 on: January 18, 2013, 07:00:57 AM »
See this thread, especially from post 3 down.  It's not an ideal solution, IMO, but it's the best we've got for now.,8019.msg32562.html

Offline philm63

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Re: calculating OG (Or sugars lost in trub)
« Reply #3 on: January 18, 2013, 07:14:23 AM »
+1 to mm658 - that's a great thread on this yet to be truly solved topic! Tom's always got a good in-depth way of putting things into perspective. Ok, now for my 2 cents...

@ Jake - You've pretty much hit the nail on the head.

The way BeerSmith calculates Trub Loss seems to exclude the sugars. This means I have to choose between a couple of methods on how I look at my recipe set-up in order to hit all my targets.

I can either lower my efficiency in my Equipment Profile to around 5-10% below actual, or I can set my Trub Loss to 0 and increase my batch size to compensate for my anticipated losses to trub - either one of these methods will get me close to my OG and volume targets. I'm actually having good luck with the increased batch size and Trub Loss set to 0 scenario - just did a 5 gallon AG batch with all new equipment and hit every target dead-on.

In the end, I'll manipulate the software to make it easier for me to figure out what goes where and when so I can consistently hit my targets, and not worry too much about what efficiency BS tells me I'm getting. I calculate that on my own, anyway. I'm more concerned with repeatability into the fermenter, not so much about bottling volumes or what some software tells my about my efficiency.
On Tap: Oatmeal Stout, IPA
Fermenting: Air
On Deck: Kolsch