Author Topic: Numbers a bit off  (Read 4055 times)

Offline Hopback

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Numbers a bit off
« on: February 06, 2011, 11:59:28 AM »
I duplicated a Full Suspension Pale Ale clone from the BYO 150 Classic Clones issue as a recipe in BrewSmith.

OGFGIBUSRMABV
BYO1.0481.01245114.6
BeerSmith1.0471.01147.19.54.71

I also duplicated a Mirror Pond Pale Ale clone from the same BYO issue as a recipe in BrewSmith.

OGFGIBUSRMABV
BYO1.0521.01340105.0
BeerSmith1.0541.01240.96.75.47

I'm Ok with most of the slight discrepancies in the numbers except for the BeerSmith SRM which seems to be noticeably low on the Full Suspension and significantly low on the Mirror Pond. Either the SRM published by BYO is off or the BeerSmith calculated SRM is off. I've re-compared my batch size, Lovibond numbers and quantities to the BYO batch size, Lovibond numbers and quantities and they look the same. Any thoughts?

Offline MaltLicker

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Re: Numbers a bit off
« Reply #1 on: February 06, 2011, 03:23:07 PM »
You use more water than the pros, diluting the color imparted by the fixed amount of grain?  Even some minor dead-loss space would change it a bit.

Offline Hopback

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Re: Numbers a bit off
« Reply #2 on: February 12, 2011, 01:28:50 PM »
I did a little checking and the SRMs in these two recipes published by BYO are just plain off, particularly the Mirror Pond clone. BeerSmith is getting them right. It has nothing to do with water used or dead space. In my system the water used is either absorbed by grain in the mash, boiled off as steam in the boil, absorbed by hops in the boil, left with the trub in my settling buckets, or goes into the fermenter to become beer. There is no dead space along the way. Some additional water may be left with the lees or absorbed by dry hops in the fermenter. The rest goes into the keg and then into me :).

Offline BeerSmith

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Re: Numbers a bit off
« Reply #3 on: February 12, 2011, 03:59:17 PM »
Hi,
 The OG, FG, ABV and Color are very easy to verify by hand (and a lot of people have checked the numbers and equations I use here) - I'm very confident that BeerSmith has the right numbers here.  You can add up the contributions of the various grains in points, multiply by your batch efficiency and divide by the total volume to get a very accurate OG reading.  Apply the average yeast attenuation to get the FG, and the ABV follows from OG and FG.  The only variable here would be what the actual potentials/yields are for the various grains you are using.

  Color is only a bit more tricky - I use the Morey equation which is easy to look up online - which basically adds up the color contributions of the various grains and then applies an exponential equation to smooth it out for higher color numbers.

  The IBU number is the only one that does have quite a bit of variation.  If you change the hop alphas, equipment settings, leaf vs pellet, boil volumes, or even the equation you use it can have a big impact on the final numbers.

Cheers,
Brad
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