Author Topic: Several problems with OG calculations  (Read 12072 times)

Offline mmmbeeer

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 7
Re: Several problems with OG calculations
« Reply #15 on: September 14, 2011, 05:52:34 PM »
I would rather be able to enter a value for mash efficiency and have the software make its calculations based on that and the post boil volume and use the water losses to account for how much water is needed.

I agree entirely.  Have to say, I'm a little surprised this wasn't fixed with v 2.0, since similar complaints surfaced with v 1.4.  That being the case, it may be unlikely we ever get our wish.

Offline BeerSmith

  • Brewer, Author, Patriot
  • BeerSmith Administrator
  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 5386
  • BeerSmith - take the guesswork out of brewing!
    • BeerSmith
Re: Several problems with OG calculations
« Reply #16 on: September 15, 2011, 09:38:49 PM »
Hi,
  So far, all of the recipes I've received where the OG numbers were way off had problems with their equipment settings or equipment profile that caused the errant calculation.

  As pointed out above, BeerSmith does use "Total Brewhouse Efficiency" (into fermenter) and not mash efficiency.  I'm considering making it optional (i.e. allowing either) for a future update, but we've used brewhouse efficiency in the program since its inception in 2003, so having the ability to support the existing user base is important as well.

Thanks
Brad
Get a free trial of BeerSmith 3 here

Offline Kurisu

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 9
  • BeerSmith 2 Rocks!
Re: Several problems with OG calculations
« Reply #17 on: December 05, 2011, 01:35:49 PM »
Rosenjm, what was the problem in your equipment setup that was causing your miscalculation?  Did you solve it?

Because I think I'm having the same trouble as you. I hit very near my estimated mash efficiency pre-boil. Then, with all the losses accounted for correctly in my equipment set up, my OG was 9 points (!) off what it should have been.  I have no idea why Beersmith told me to use the amount of grain it did, and then I came up so short on my FG in my post-boil.


Offline BeerSmith

  • Brewer, Author, Patriot
  • BeerSmith Administrator
  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 5386
  • BeerSmith - take the guesswork out of brewing!
    • BeerSmith
Re: Several problems with OG calculations
« Reply #18 on: December 05, 2011, 01:47:03 PM »
Hi
  If you send me some sample recipes I would be happy to take a look at them. My email is beersmith at my beersmith.com domain name.

Brad
Get a free trial of BeerSmith 3 here

Offline Kurisu

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 9
  • BeerSmith 2 Rocks!
Re: Several problems with OG calculations
« Reply #19 on: December 06, 2011, 06:02:23 PM »
Hi Brad,

I think I might have found part of my problem -- I think my boil off rate was too ambitious, that contributed at least a couple points difference. The other point might have come from me overestimating my mash efficiency. From my calculations I have an Est. Mash Efficiency of 77%, but as measured in this batch I seemed to get only 74.5%.  I tried to compensate with a longer boil, but that didn't fix it enough. (I boiled for an extra 25 minutes).  That resulted in a 6 point different (not 9 -- I was mistaken above).

I've attached my recipe (Stone Ruination Clone).  Is there anything in there you can see that is drastically wrong?

Offline BeerSmith

  • Brewer, Author, Patriot
  • BeerSmith Administrator
  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 5386
  • BeerSmith - take the guesswork out of brewing!
    • BeerSmith
Re: Several problems with OG calculations
« Reply #20 on: December 06, 2011, 09:14:46 PM »
Hi,
  I think it looks pretty good - if you enter the "actual" Pre-boil vol/gravity into the Mash Details you can get your "measured mash efficiency", and also if you go to the fermentation tab and enter your measured FG and measured volumes you will get to see the "measured efficiency" based on those values.

  Therefore after you brew a batch - enter these measured values and you will get a very good idea what your total brewhouse and mash efficiency numbers are - use the measured total brewhouse efficiency as the basis for formulating your next recipe.

Brad
Get a free trial of BeerSmith 3 here

Offline Kurisu

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 9
  • BeerSmith 2 Rocks!
Re: Several problems with OG calculations
« Reply #21 on: December 07, 2011, 10:20:55 AM »
Thank you for the look Brad, that's helps ease my worries. I think the high gravity of the beer led to a lower mash efficiency than I got last time.

Is there a general rule of thumb for adjusting Est. mash efficiency when increasing the size of the beer? (Or in this cash, brewhouse efficiency -- but I find it simpler to think in terms of est. mash efficiency.)

Secondly, can anyone tell me what Rosenjm's issue was and how it was resolved? From his argument near the beginning of the thread it looked like he really did find a problem with how Beersmith calculates expected OG.


Offline BeerSmith

  • Brewer, Author, Patriot
  • BeerSmith Administrator
  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 5386
  • BeerSmith - take the guesswork out of brewing!
    • BeerSmith
Re: Several problems with OG calculations
« Reply #22 on: December 07, 2011, 01:50:44 PM »
Hi,
  If you are brewing higher than normal gravity beers your efficiency is going to be lower because you are running a lot less total water per pound of grain through the mash.
   http://www.beersmith.com/blog/2010/05/09/how-to-brew-big-making-high-gravity-beers/ - Article on it

  The issue (Rosenjm's) with boil time not changing the numbers was resolved in an early patch - you can now specify in the equipment profile a "rate" of boil off.  His other issue is really related to the difference between batch and mash efficiency - which is why I pointed him to the article.  Since the program uses overall batch efficiency you can easily arrange your volume losses do not align with what a mash efficiency calculation would tell you.

Brad
Get a free trial of BeerSmith 3 here

Offline Kurisu

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 9
  • BeerSmith 2 Rocks!
Re: Several problems with OG calculations
« Reply #23 on: December 07, 2011, 04:23:45 PM »
Wow, I noticed in your article that big beers can reduce efficiency from (say) 72% to 60%.  That's a big drop.  I only lost around 4%, so I guess that's pretty good.

So, I guess there's no way to estimate the loss in efficiency?  It would be nice to have a rule of thumb. Say, 1% efficiency drop for every pound over a typical 10lbs?

Anyway, thanks for the help. I feel more confident about what the problems were and I can't wait to try again!

Offline edweller

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 8
Re: Several problems with OG calculations
« Reply #24 on: December 07, 2011, 05:27:01 PM »
Just my 2 cents about big batches and loss of efficency.
That is exactly why I have 2 different size coolers for mash tuns.
I always use 1.5 qts per pound and get great numbers, normally low 80's for Mash efficency.
Before I had my second larger cooler for my big beers my numbers were not near as good on them as soon as I got down to 1.25 or less to fit the smaller cooler.
I always try to keep the batch to cooler size such that it is nearly full to keep the heat in.
Thats what works well for me.
Doing this the software is normally real close on everything I brew.

Ed
Brewing Beer For A Better Tomorrow





Brewing Beer For A Better Tomorrow

 

modification