Hey Dave,

How is BrewMate calculating preboil wort gravity?

First I calculate the Preboil Wort Volume using the user defined Percentage of Evaporation (which defaults to 10%)

PreBoilVolume = Batchsize * (PercentEvap) / 60.0) * BoilLength / 100

Then I calculate the Preboil OG as follows

PreboilOG = Batchsize * (OG - 1) * 1000) / ((PreBoilVolume - 1) * 1000);
PreboilOG = PreboilOG + 1;

Then i work out the average as follows

AverageOG = ((PreboilOG + OG) / 2);

I will go thru the formula more thoroughly as soon as i get a minute as it interests me as well

Speak soon

Rob.

i've had another couple of minutes to have a look and this is what values i'm getting now using your recipe

Boil Factor .219
Bigness 1.321
utilization .289
preboil 1.024

this gives me a result of 20.79 ibu

and your suggesting the formula is designed for pellets? so it has to be reduced by 10% for flowers. I'd always assumed the formula was based on flowers and timed it by 1.1 for pellets and 1.02 for plugs!

Where does the 'Tinseth Concentration Factor' come into play (i se beersmith has a default of 1.3?

thanks for persisting

Rob.

I can remember now why i adjust for pellets or plugs in the Tinseth Formula because in the original documentation i read it stated "that his table is optimized for fresh whole cones loose in the boil"

and the Rager formula is designed for hop pellets and has to be adjusted for leaf or pellets.

It looks as though you're right! The Tinseth formula was designed to give the IBUs of Whole Hops cones, not Pellet hops. It seems my own calculations (and Beersmith) might have it backwards. I've posted something over on Beersmith's forum to see what they might have to say about it.

Great job! And thanks for hashing that out with me!

I'll be downloading the newest version of BrewMate very soon, and I'll give it another evaluation. I think the timer alarm for hops additions is really going to be a user friendly add on to the program. I'll probably be using it myself from time to time.

Keep up the good work!

Hey Dave,

More than happy to be nutting this out with you, I've had to question many things while writing this program and haven't fallen in the "because thats the way everyone else does it" category

After the discussions with you i have made some adjustments to my bitterness calcs (that will be in the next release of BrewMate)

I know it only makes a smidge of difference but my calculations now use the Average OG and Average Volume to calculate Hop Bitterness.

The program also allows for "Average" Bitterness calc which takes the average of Tinseth and Rager so if you have no idea which one a recipe was designed in you could use that

I am also working on Paturization Units (PU's) and a continuous isomerization calculator for those that No-Chill so they can work out their bitterness correctly that is why I really need to get the core Bitterness Calcs Correct

Cheers Rob.

Just downloaded the program just took a quick glance at it and it looks pretty good. can't wait to start using it.

Hey coopertj12,

Thanks for giving BrewMate a spin

Cheers Rob.

i only have one complaint about your program...


i'm using a mac....

any way to get a mac version of this software???