Beersmith calcs

[Sokrateez]

So I've been trying to fine tune my brewing process, but one thing that I noticed from my last batch was some strange gravity readings and strange results from beersmith.

I intended to collect a total of 5 gallons of beer in the fermenter, so whenever i set up my beersmith equipment profile, I punched in boil time of an hour, left the default evapouration rate (at 11%), "lost to trub and chiller' (at half a gallon), and cooling loss (at 4%). After I put my target volume at 2.5 gallons (since I'm doing a split boil in 2 pots), it gives me the figure of 3.49 gallons.

But as per my understanding, evapouration is what concentrates the wort and leaves you with the higher gravity. So if I had 7 gallons and lost 11%, I would be left with 6.23 gallons, which according to calculators will only increase the gravity from 1.036 to 1.040 (when my target is 1.050, which is what a reduction from 7 to 5 gallons should yield).

So are the trub and cooling loss values (which are the numbers that actually bring the total "wort volume" to target) concentrating the wort as well? Or am I thinking of something wrong. Just trying to zero in my gravity-going-into-the-fermenter values now, since my mash efficiency is pretty much bang on. I'm thinking too that the fact that I'm doing a split boil is causing me to collect too much wort out of the mash, when I may not need so much. Thoughts?

 

[PurpleJeepXJ]

Are you at a simmer or a rolling boil? Splitting the batch should not throw you that far off. Are you sure your efficiency is dead on? Does not sound like it since your numbers are off and that would be the first place I would start.

 

[Yooper]

Well, splitting the batch will double the boil off, right? Boil off by a percentage isn't really the right way to do it.

I have a 15.5 gallon keg that I boil in. If I make a 5 gallon batch, I start with 7 gallons. If I make a 10 gallon batch, I start with 12 gallons. The reason is that the boil off is the same, no matter what the volume is, if the pot is the same. If you boil off a gallon an hour in each pot, that is simply the way it is.

I don't know why Beersmith figures it at a %- that's not real world. So, fix the % simply to give you the real figures in the software.

 

[PurpleJeepXJ]

@Yooper
Isn't it more based on surface area rather than % or is that what you are saying?

 

[Yooper]

@Yooper
Isn't it more based on surface area rather than % or is that what you are saying?

Yes, that is exactly what I'm saying! Or rather, attempting to say!

If you use the same pot, your boil off can't change due to batch size. So, a "% to boil off" isn't at all realistic. It's not really based at all on percentage. That makes Beersmith hard to tweak at first.

 

[PurpleJeepXJ]

That's a very good point... and we all know that the 'Mash Setups' provided with BeerSmith need a good amount of personal tweaking.

 

[diS]

I noticed that BS calculates cooling loss when wort is at 212F (default 4% temp. adjustment), but it is closer to 150F because Boil Volume is volume prior to the start of the boil- from BS help.
So it would be more like 2% because 150F is about halfway between room temp and boiling.