Brewing Software Ingredient Profile Differences

[crayzeeguy]

Hello all,

I have recently begun exploring new options for home brewing software. As a test, I run the same recipe through various packages and calculators in order to analyze the features and functions. I have noticed a significant variation in the way multiple packages calculate OG and FG from the inputs. One single recipe returned final ABV of anywhere from 6.6% to 7.5% across the various packages I have tested. Although the same ingredient profile is being entered in each package, it appears each software package is assigning different values for SG of particular malts as well as different yeast attenuation percentages.

I ask of you, is this normal? When i brew, I am never overly concerned when i miss OG or SG, but if I was designing a recipe, I would feel very mislead if the ABV ended up off by almost a whole percentage point. Are there any software packages you would classify as more accurate or more inaccurate than others?

Thanks for the assistance!

 

[brewfun]

Starting with them right of the shelf, there can be very wide differences. In each case, it's up to you to narrow the inherent variables to match your particular system and brewing style.

Equipment:
Does the software work from mash or brewhouse efficiency? These are different measurements of efficiency and have very different ways of being calculated. In fact, Brewhouse Efficiency uses mash efficiency as part of its equations but not vice versa.

Do you have trub loss or other losses accounted for correctly? For an off the shelf comparison, I'd leave accumulated loss at zero, simply to remove the variable.

Boiloff concentration may be different between the software packages. Make sure the boiloff rate and boil time match up.

Grains
Make sure each grain has the same potential and color. Grain analysis reports vary from year to year and some maltsters are more diligent about updating their averages than others. The specs found online usually represent minimum targets, rather than results. So, if a software package is using averages from malt analysis, then their numbers could be higher than the targets.

Other variations could be how each software is calculating grain absorption, cooling shrinkage, rounding of numbers, fermentability by mash temperature and any other number of details. Look for the option to customize these numbers as you get more familiar with your system.

So, without any customization, I think just a point of alcohol difference isn't too bad. If all the available customizations are the same, it will come down to the look and feel that you like better.

 

[crayzeeguy]

Thanks for the detailed and informative reply. Part of my initial testing of each package was to enter all of the same brewhouse specifics such as boil kettle diameter, boil off rate, trub loss etc. into the packages and calculators (Beersmith, Brewers Friend, iBrewMaster, TastyBrew etc.)

Looking into it a little more, I discovered that the Preboil OG was fairly spot on amongst all of the various packages (~1.045 target for a particular IPA with the packages coming in at 1.041-1.049). OG and FG are where the variations really began to take shape. The fact that attenuation for a particular yeast (Safale-05) ranged from 68% to 81% explained much about the FG variances. I am still researching why the post boil OG varies so much between packages.