Hey all,
how do you go about calculating hops to use when you dilute wort ... by this i mean the following:
planning a brew for 46 litres of 1.048 beer.
will put about 44 litres into the kettle which will boil down to close enough to 38-40 litres, then will dilute it back up to 46 in fermenter.
I've figured out the modifications needed to grains in order to hit my FG of 46L @ 1.048% however having troubles calculating hops.
bittering schedule is:
4.6IBU @ 60 mins
22.5IBU @ 45 mins
6.7IBU @ 30 mins
Using formula from BYO mag for bittering which is:
IBU = (weight of hops in ounces x alpha acid % x utilization %) / (volume of final batch in gallons x 1.34*)
*constant to convert measurement into US standards
(i've reworked the formula to give me weight from a given ibu)
I'm using another formula for utilisation which takes into account the SG of the boil (higher than the final) which gives me poorer util than a lower SG wort, plus my volume is lower than my final target volume which will give less util during the boil as well. Using the lower util and lower volume of boil will end up with a weaker IBU than planned.
how do I scale my IBU's into the boil to give me the correct final IBU's in the fermenter? Is there a method which takes into account target final volume and SG compared with boil volume and SG to scale the IBU?
Hope this makes sense...
thanks!
how do you go about calculating hops to use when you dilute wort ... by this i mean the following:
planning a brew for 46 litres of 1.048 beer.
will put about 44 litres into the kettle which will boil down to close enough to 38-40 litres, then will dilute it back up to 46 in fermenter.
I've figured out the modifications needed to grains in order to hit my FG of 46L @ 1.048% however having troubles calculating hops.
bittering schedule is:
4.6IBU @ 60 mins
22.5IBU @ 45 mins
6.7IBU @ 30 mins
Using formula from BYO mag for bittering which is:
IBU = (weight of hops in ounces x alpha acid % x utilization %) / (volume of final batch in gallons x 1.34*)
*constant to convert measurement into US standards
(i've reworked the formula to give me weight from a given ibu)
I'm using another formula for utilisation which takes into account the SG of the boil (higher than the final) which gives me poorer util than a lower SG wort, plus my volume is lower than my final target volume which will give less util during the boil as well. Using the lower util and lower volume of boil will end up with a weaker IBU than planned.
how do I scale my IBU's into the boil to give me the correct final IBU's in the fermenter? Is there a method which takes into account target final volume and SG compared with boil volume and SG to scale the IBU?
Hope this makes sense...
thanks!
