Water requirements 60min vs 90min boil

OkanaganMike

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Hey guys question for you. If I wanted to play with a 90 minute boil from the standard 60 minute boil, where and how do I do this so it takes the increased water boil off rate into consideration?
I just ran a test with 2 identical recipes and with the only difference being the hop addition at 90minute vs 60minute and water requirements were unchanged.

Is this a manual calculation or is there any way to tie the boil off rate to something other than the hop addition boil time?

Thanks in advance.
 
Hey guys question for you. If I wanted to play with a 90 minute boil from the standard 60 minute boil, where and how do I do this so it takes the increased water boil off rate into consideration?
I just ran a test with 2 identical recipes and with the only difference being the hop addition at 90minute vs 60minute and water requirements were unchanged.

Is this a manual calculation or is there any way to tie the boil off rate to something other than the hop addition boil time?

Thanks in advance.
It's in the recipie editor it should add to your required brew water requirements.
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When I changed the boil time in this recipe the water requirements changed with it.;)
 
As long as the boil vigor is consistent the boil off will be 1 1/2 times as much as the 60 minute boil. The primary factors that determine your boil off rate are boil vigor and surface area. As Ben said, BF will do the calculation using the time you enter.
 
Indeed! What those guys said about your system's kettle size and boil vigor keep in mind the outside environment things like your relative humidity and altitude. I'm not that high here in the foothills of south central PA, only about 500 feet but I have noticed a big difference brewing on really dry days. I don't see a location in your tag OMike but if you are somewhere like me where the humidity swings as much as 60% it can make a difference...not huge but one that I take into account that I'll drop an extra quart of into the mix on those dry days. I should probably add that I am not a recipe editor user!
 
Indeed! What those guys said about your system's kettle size and boil vigor keep in mind the outside environment things like your relative humidity and altitude. I'm not that high here in the foothills of south central PA, only about 500 feet but I have noticed a big difference brewing on really dry days. I don't see a location in your tag OMike but if you are somewhere like me where the humidity swings as much as 60% it can make a difference...not huge but one that I take into account that I'll drop an extra quart of into the mix on those dry days. I should probably add that I am not a recipe editor user!

Right you are.
Less influential factors, but nonetheless may change the resulting boil off. I didn't mention humidity, because it will be a variable regardless of boil size, and isn't usually factored in. As for altitude, unless the OP was brewing in a different location, it would be a constant.
 
Indeed! What those guys said about your system's kettle size and boil vigor keep in mind the outside environment things like your relative humidity and altitude. I'm not that high here in the foothills of south central PA, only about 500 feet but I have noticed a big difference brewing on really dry days. I don't see a location in your tag OMike but if you are somewhere like me where the humidity swings as much as 60% it can make a difference...not huge but one that I take into account that I'll drop an extra quart of into the mix on those dry days. I should probably add that I am not a recipe editor user!

The general rule that a 90 minute boil boils off 1.5x that of a 60 minute boil is not exactly true but I for one can't measure the difference between the actual rate, which increases over time (less liquid to heat) and the rule of thumb of 1.5x. I'm not really worried about that 250 ml of liquid. As to humidity, hard to predict its effect. I brew indoors so the humidity rises as the boil progresses. Here's your work-around for that: Have some DME (or sugar of your choice) and some boiled, cooled brewing liquor (water plus treatments) available to make up the difference. If I were running Coors, I'd put my mad engineering skills to work to account for these differences. At a homebrew scale, it's not worth it. Altitude doesn't make that much of a difference in the rate, but it affects the temperature of the boil substantially: Water boils here at 202 degrees F.

When I do a 3-gallon batch, variation in boil-off rate is more meaningful but still, since 90 minutes is a standard boil for me, I don't have to worry about wind and my heat, an induction cooktop, is constant, I can use the average boil-off rate and be accurate enough I can fix it, if necessary, with water or DME in the fermentor.

It's the craft part of craft brewing: Knowing what makes a difference in your outcome and how to correct it if necessary. That, and knowing the basic dilution equations.
 
Accurate predictions seldom happen when ~ is part of the equation, and when they do, it's called luck :)
I'm with you on compensating for small variances after the fact if I deem it necessary.
 
Accurate predictions seldom happen when ~ is part of the equation, and when they do, it's called luck :)
I'm with you on compensating for small variances after the fact if I deem it necessary.
It's that little epsilon in every equation worth solving, the one we six-sigma geeks hate so much, variation.
 
Thanks Trialben, I thought it was around somewhere and just glaze over it every time lol. I've got my 60min boil time down and don't typically bother with 90 min boils as I don't use Pilsen but wanted to try a Sierra Nevada recipe from their site. Ended up tweeking to a regular 60min boil anyways as I didn't want to fart around with the water. Figured 1.5X would get me close enough but was pretty sure math was here somewhere already.
Cheers to all who commented!
 

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