Author Topic: How does Beersmith estimate FG?  (Read 2640 times)

Offline slightlyoffbeat

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How does Beersmith estimate FG?
« on: February 04, 2017, 12:13:57 AM »
I know most people do something along the line of:

GP = (1 - attenuation%) * (Original gravity points)

But I realized that that equation would never allow for a FG lower than 1.000. There must be a better way. I know beersmith can estimate a FG lower than 1.000. Any chance of sharing how that is calculated?

Cheers.

Offline BeerSmith

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Re: How does Beersmith estimate FG?
« Reply #1 on: February 04, 2017, 08:38:06 AM »
In general it applies the average yeast attenuation number to get the FG estimate.  However an additional factor is added in based on mash temperature if you are brewing all grain which accounts for higher/lower attenuation due to mash temps.  Finally BeerSmith adds an additional factor for sugars which are nearly 100% fermentable and generally reach higher attenuation than malt.  This is handled based on the gravity contributions of the sugar and can drive the FG below 1.000.

What is missing is a limit due to alcohol, as I don't currently have the alcohol limits for the yeast as part of the record.  I am hoping to add this for a future update.

Brad
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Offline slightlyoffbeat

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Re: How does Beersmith estimate FG?
« Reply #2 on: February 05, 2017, 12:25:31 AM »
Thanks! I appreciate you taking the time to answer my questions. Love the software and your attention to details.

Cheers.