Beersmith water & orig. gravity calcs don't seem to work right

[JoePerri]

Hi all,

I asked this question over at the Beersmith forums but did not get an answer. Does anyone here have any ideas?

Perhaps I'm not the sharpest knife in the drawer or I'm missing something obvious but the water and gravity calculations don't seem to work properly. It seems the OG calculation is only related to grist bill & "Batch Size" field. Nothing else changes it. This is a problem. I'll give a simple example. Lets say I want to collect 5 gallons of 1.040 wort into my fermentor. One would think that I should set my batch size to 5 gallons and add grains to hit 1.040 based on my brewhouse efficiency. But I also need to keep in mind the amount of water needed and wort lost elsewhere in the process. BS provides a handy tool to calculate and keep track of all these issues, boil-off, deadspace, etc. My kettle holds about .75 gal of lost wort in the trub and dead space. If I set this value to .75 in Beersmith it correctly back-calculates the water needed at the start of the boil. HOWEVER it does not change the OG to reflect the fact that I am now brewing 5.75 gallons of wort! A simple experiment will show this and why it is wrong. Go into BS and set the "Lost to Boil Trub & Chiller" value to 10 gallons. You are now making 15 gallons of beer with the same amount of grain yet the OG does not change! In my set up I really do need to end up with 5.75 gallons of wort to get 5 gallons into the fermentor. Of course I can just change the batch size to 5.75 gallons and set the trub/chiller loss to 0 and get the right OG but that is counterintuitive and makes the trub/chiller loss field useless. There are other fields that behave in the same way. Of course the efficiency calcs are completely wrong in all cases because they take none of these losses into effect. Am I missing something here?

Thanks,
Joe

 

[JoePerri]

Anybody?


Joe

 

[Amiaji]

Doesn't appear anyone has an answer.

 

[JoePerri]

Yep.

I don't think I'm missing anything, I think Beersmith just has several fairly large bugs in how it does the calculations.

Joe

 

[thedude123]

I just posted it again in the beersmith forum I will let you know if i get a response.

 

[thedude123]

Here is what I got as a Response:

"Hi,
The brewhouse efficiency (by definition) includes the losses you describe - it is the "gross" efficiency for your brewing system. An alternative would be to use the MASH efficiency and then calculate forward from there (using trub loss, boil loss, etc...) to get the final OG.

Most brewers use brewhouse rather than mash efficiency when formulating recipes, which is also what BeerSmith does. I'm considering adding an option to allow calculating from mash efficiency instead for a future version.

Here's more on the topic including how to calculate it by hand:
Brewhouse Efficiency for All Grain Beer Brewing | Home Brewing Beer Blog by BeerSmith

Cheers,
Brad"

 

[thedude123]

This is what someone else said on the board-

"I was able to duplicate your findings and I see what you mean; however, I think the problem lies in what BSmith is designed to do. Instead of deadspace loss, think of spilling a gallon on the floor. BSmith cannot predict that size loss after you've entered a prediction of spilling only 8 ounces. Once you tell it that you spilled a gallon, it can tell you you'd better use more grains and water next time (if you want to fill the carboy.)

BSmith is designed to take the specs and conditions that you have documented on your equipment in the past, and it then does the grunt work math for us, for future batches. Equipment Profile settings do not appear to be interactive like EE% and Batch Size. (Perhaps logically, because it is hard to imagine that the deadspace lost would suddenly increase from 0.75 gallons to 2.0 gallons during a brew.) If it somehow did, then you'd click on "Brewhouse Efficiency" and enter a new Actual Batch Volume of 4.50 gallons, reflecting the additional loss of 1.25 gals. BSmith reflects this as a 16% decrease in efficiency (down to 59% instead of the 75% I used), because it believes the deadspace to be 0.75 gals. IF this condition was expected to persist, then you'd either enter a 2.0 gallon loss in your equipment profile, or you'd enter a 59% efficiency for the next batch and use more grain. Or change your batch volume to 4.50 gals. Either way you have to tell BSmith what to expect and then run with that thru the entire process. (Software-wise, that may be why the equipment choice is made before any ingredients are selected.)

Also a good example of why it is vital to measure all the key stats on each brewing rig in order to get meaningful forecasts from BSmith. All the losses, the evap rate, the batch size, etc., are believed to be correct by BSmith when it calculates OG and everything else."

 

[FlyGuy]

Joe, I certainly see your point here. But this really isn't a bug, its more that you have an expectation the program should do something that it was not designed to accomplish.

The replies that were posted here don't say it very well, but the bottom line is that you must know your own brewhouse efficiency for Beersmith to work properly. It is an INPUT variable that Beersmith relies upon to determine its gravity calculations. When you added ALL that water to offset deadspace losses, Beersmith expected YOU to also appropriately adjust your brewhouse efficiency accordingly, as well. The software doesn't try to do that adjustment for you -- it would be somewhat onerous to predict the change in efficiency mathematically, and like the other responder said, there just isn't a need for the program to make these sorts of predictions.

Bottom line -- you can't change brew parameters like deadspace losses without impacting your brewhouse efficiency. You kept that input constant, and that's why the software kept coming up with the same gravities (even under those ridiculous scenarios).

 

[JMD87]

Joe, I certainly see your point here. But this really isn't a bug, its more that you have an expectation the program should do something that it was not designed to accomplish.

The replies that were posted here don't say it very well, but the bottom line is that you must know your own brewhouse efficiency for Beersmith to work properly. It is an INPUT variable that Beersmith relies upon to determine its gravity calculations. When you added ALL that water to offset deadspace losses, Beersmith expected YOU to also appropriately adjust your brewhouse efficiency accordingly, as well. The software doesn't try to do that adjustment for you -- it would be somewhat onerous to predict the change in efficiency mathematically, and like the other responder said, there just isn't a need for the program to make these sorts of predictions.

Bottom line -- you can't change brew parameters like deadspace losses without impacting your brewhouse efficiency. You kept that input constant, and that's why the software kept coming up with the same gravities (even under those ridiculous scenarios).

Nicely put. Just to add my example... my LHBS has a mill that I use for free. He seems to constantly adjust the mill, probably because lots of people use it. I crushed some grain yesterday and noticed it was a very very fine crush. I know when I get a crush like this, my efficiency is around 85%, so I went back and adjusted my efficiency in beersmith and removed about a pound of grain to hit my OG.

It's all about assuming what your efficiency will be, so now that you know your deadspace accounts for one or two points loss in efficiency (hypothetical #), you can be sure to make sure you adjust your next efficiency % accordingly.