This article may help: https://byo.com/article/hop-stands/

 

It always bothers me when articles aren't dated. Luckily I have a subscription to the magazine and found it in the March-April 2013 edition after a search through my magazines.

 

I'm very new here. Does BF provide the formulas for their utilities? I love the math behind brewing and could look into it if the formulas are available.

 

at least the whirlpool additions show what it is on the recipe builder. Add a whirlpool hop addition and it automatically shows 10% hop utilization.

 

That seems reasonable. Beersmith also uses 10%.

 

Got a few pounds of homegrown Centennial hops in the freezer I am trying to stuff into my brewing. So far what I am finding out is they don't have the IBU's of commercial. With soil additives I should be able to fix that but in the mean time I've been throwing them in in later additions. I did a few every 20 min. additions with some success, the aroma and added grapefruit tang was grreat but they do not have the bittering oils they should have. Use lots and grow more!!!

 

At least the IBU calculator does not seem to have an option for whirlpool hops. When you put in "0" for minutes, the calculator does not add any IBU's.

 

That's always been a mystery to me, too. And since FO hops would be left in during whirlpool, they'd be going along for the ride there, too. If no-chill extended boil is a factor in FO hop contribution, you'd have to consider that whirlpool would add the same amount.
It'd be interesting to spit a batch and do only FO and only Whirlpool to see which is more bitter. I'm going to bet on the FO since it's in contact with

 

But if the whirpool option is considered significant, why is that option also not included in the "IBU Calculator"? At the very least, there should be some mention, or caution, that additional consideration should be taken if one is whirpooling hops.

The bottom line, is that "0 minutes" is quite ambiguous and could mean different things to different people (i.e. flameout and rapid cooling; flameout and slow cooling; or whirlpooling at various lower temperatures and lengths of times after flameout). Might be interesting to develop a separate IBU calculator for different options after flameout.

 

this all confuses me. the calculator absolutely has an option for whirlpool. choose whirlpool instead of boil next to the hop addition. then it adds IBUs. Then choose your utilization factor based on what temp you whirlpool at. Forget the 0 min addition unless you aren't doing a whirlpool.

 

The confusion lies in the difference between the "Recipe Builder", and the separate tool - "IBU Calculator - Bitterness". This separate tool does not include the whirlpool or hopback option (the Recipe Builder actually handles it quite well) .

See:
https://www.brewersfriend.com/ibu-calculator/

 

Looks like someone has already done this. Here's an excellent article on an algorithm that calculates hop utilization after flame-out, based on the Tinseth formula:

https://alchemyoverlord.wordpress.c...-ibu-measurement-especially-for-late-hopping/

 

The bitterness i get out of an 30min 80c hopstand is negligible i find. I just recently whirlpooled 60g of 18%aa Eureka hops for half hour above 80c and i thought that beer was lacking bitterness it was reading high 40s IBU. I set my utilization at 5%.

Mines more of a hop stand than a whirlpool to BTW with the odd stir every 5-10 minutes or so.

 

Any hopstand close to 80 C would be negligible since 80 C is about the cut-off point for isomerization. The length of time to drop from 100 C to 80 C could give additional IBU's.

Another very simple option if only cooling is involved, is to add to the boil boil length about half the time it takes to cool to 80 C (e.g. if actual boil length of the hops is 60 minutes, and the time from flameout to 80 C is about 10 minutes, set the boil length to 60 + 1/2 time to cool to 80 C, or 60 + 5 = 65 minutes).

The whirlpool or hopstand is more difficult to estimate since it depends on the temperature and length of time. A very simple estimate could be to add the result of the following equation to the boil length:

((Temp. Whirlpool in C - 80)/20) x (Length of Whirpool or Hopstand in min.)

For example, if the whirpool was done at 85 C for 16 minutes, then add:

(85 - 80)/20 x 16 = 4 minutes.

Thus you would set the boil length to 64 minutes instead of 60. In addition, you would also add an estimate for the time it took to cool from 100 C to 85 C as explained above.

Of course, this only accounts for the initial hops. Another estimate has to be added for the additional hops added after flameout. But since flavor/aroma hops are usually low alpha, it should not contribute too much in terms of additional IBU's.