Late hops - less IBUs than if just steeped? BS not adding in steeping time?

[Gadjobrinus]

Loving the program but still figuring it out. Can't be sure but it seems that hops added at least 5 minutes before knockout are presumed to be steeped, because the resulting IBU figure seems reasonable; but doing a brew with several hops added at 3 minutes before knockout, then steeped as with all the others, I am getting a significantly under-reported IBU. In other words even if boiled for 3 minutes then steeped, I get significantly higher reported IBUs if I just call the 30 minute steep than if I call them boiled for 3 minutes. I thought BS defaulted to include late hops in the steep calculations as well as their boil contributions.

Is there a way to make sure late hops are also calculated for their WP/steep contributions?

 

[VikeMan]

It sounds like BS is behaving the same as other programs in this respect, i.e. in that any hop addition is either treated as boil or post boil (depending on where it's entered), but not both. My BrewCipher, which happened to be the first program to support post boil addition IBUs, does the same thing.

A potential workaround for you, strictly to estimate IBUs, might be to add (in the program, not in the kettle) the same hops twice, once at 3 minutes and once at flameout/steep. The flameout/steep IBUs would be slightly overstated, as some percentage of the alpha acids would have been used up in those last 3 minutes. But you could probably come up with a pretty good rule of thumb, using a one time hypothetical batch, to factor against those steep IBUs. Perhaps something like...

- Calculate (in BS) what a 90 minute addition of an ounce of hops (pick any hop) would yield. Let's say the answer is 30 IBUs. (I picked 90 minutes because the utilization curves gets very flat beyond that.
- Calculate (in BS) what a 3 minute addition of an ounce of hops (pick same hop, and same hypothetical batch) would yield. Let's say the answer is 3.5 IBUs.

With the above (made up) numbers, we'd say that the initial 3 minutes uses up 3.5 IBUs / 30 IBUs = ~12% of a hop's approximate potential. Thus, ~88% have not been used. So you could apply this rule of thumb by multiplying your (in BS only) flameout/steep addition weight by 88% before entering. You could use this 88% rule of thumb any time you are doing a 3 minute addition that carries over into the steep.

 

[day_trippr]

You have to set the temperature of any non-boiled additions!


Cheers!

 

[Gadjobrinus]

It sounds like BS is behaving the same as other programs in this respect, i.e. in that any hop addition is either treated as boil or post boil (depending on where it's entered), but not both. My BrewCipher, which happened to be the first program to support post boil addition IBUs, does the same thing.

A potential workaround for you, strictly to estimate IBUs, might be to add (in the program, not in the kettle) the same hops twice, once at 3 minutes and once at flameout/steep. The flameout/steep IBUs would be slightly overstated, as some percentage of the alpha acids would have been used up in those last 3 minutes. But you could probably come up with a pretty good rule of thumb, using a one time hypothetical batch, to factor against those steep IBUs. Perhaps something like...

- Calculate (in BS) what a 90 minute addition of an ounce of hops (pick any hop) would yield. Let's say the answer is 30 IBUs. (I picked 90 minutes because the utilization curves gets very flat beyond that.
- Calculate (in BS) what a 3 minute addition of an ounce of hops (pick same hop, and same hypothetical batch) would yield. Let's say the answer is 3.5 IBUs.

With the above (made up) numbers, we'd say that the initial 3 minutes uses up 3.5 IBUs / 30 IBUs = ~12% of a hop's approximate potential. Thus, ~88% have not been used. So you could apply this rule of thumb by multiplying your (in BS only) flameout/steep addition weight by 88% before entering. You could use this 88% rule of thumb any time you are doing a 3 minute addition that carries over into the steep.

Awesome, I'll play around with that, thanks!

 

[Gadjobrinus]

You have to set the temperature of any non-boiled additions!


Cheers!

Thanks man, I do that and the function of estimating a pure WP or hopstand addition is a great feature. What I'm talking about though is as Vikeman mentioned - calculating the total IBUs of a late boil hop addition, carried over into a WP/stand. I.e., a lot of times I might do a 3-5 minute boil on a hop or hops, then WP and stand for 30 minutes. BS doesn't seem to do this automatically, because a 5 minute boil is less than if the same hops were shown at knockout + 30 minute steep. Since the 5 minute boil also steeps, it should be more.

Just an example:

Hops at 3 min:

Shows 35.6 IBU and .61 BU:GU.

Same hop charge, 30 min. WP/Steep:

Shows 47.6 IBU and .82 BU:GU (which in this bitter is what I'm shooting for actually). Pretty huge difference.

 

[Gadjobrinus]

Wait - I just noticed that when you do a boil addition, it actually says boil/steep:

-yet, this is the charge that yields a low, I think really underreported, IBU. Puzzled. I believe for this particular "equipment" profile I did set a 30 min. WP/steep. So is the program actually presuming all hops, even those at 3 min. boil, are steeped? And if so, why would a 5 min. boil hop actually show lower in IBUs than the same hop added at knockout in BS, for a 30 min. steep?

Hmm.