Back bittering with hop tea?

[butterpants]

I've got a batch of ESB and English Barleywine (were done partigyle) that suffered from low hop utilization from a different (stainless steel mesh... too fine) hop spider design I used. I'd like to bump up the IBUs on each between 5 and 10, tasting as I go. Seems if I make a small concentrated batch of hop tea and boil it long enough to isomerize a "back bittering" can be done by strained, concentrated additions to each keg.

Now my questions.... as I'd like this to be fairly repeatable and moderately scientific.

1) How can I calculate the IBUs such a tea would impart to a give volume of tea? Then how to measure out the effect on a 5 gallon batch?

2) How long to boil? If 60 minutes do you run into issues with too much evap in lets say a small tea kettle? Can you just top up with tap water if volume gets low?

3) Strain the hops out with a coffee filter post or keep them in a paint strainer mesh bag for the whole
boil?

4) Could I store this back bittering concentrate for later use without a substantial loss in ibu power?

5) Which hops to use? (was thinking high AA and clean... like Magnum)

Thanks for any advice.

 

[billl]

I don't think you are going to get the results you hope for. You aren't going to get above 100IBU in a boiling process. A pint of that in a 5 gallon batch would be dilluting it by a factor of 41, or something like a 2 IBU bump. Scaling up to 10 IBU would be something over a half gallon of hop tea and would definitely impact your overall flavor.

They do sell much more concentrated hop extract.

http://morebeer.com/products/isohop-bitterness-extract-1-oz.html

 

[butterpants]

Couldn't I just condense/concentrate it?

Thanks for the link it's actually exactly what I'm looking for.... just hoping to do it at home!

 

[billl]

Well, someone else has figured out how to do it, so you can theoretically do it too. It's not just condensing though. There is a saturation point around 100IBU that you just can't get beyond with boiling. All the products seem to claim a separation process involving liquid CO2

 

[butterpants]

Copy that. Chemical extraction. I might just buy some.

 

[agrazela]

Looks like the stuff at morebeer is discontinued?

Anyway, here's something similar that I use from time to time to super-bitter IPA's and IIPA's:
http://www.hoptech.com/products/iso-alpha-extract-2-oz

According to my calculations, 1 gram of the iso-alpha per gallon of beer equals an added 8 IBU.

 

[butterpants]

I did see the hoptech stuff while googling... way cheaper than morebeer too.... im going to pick some of that up. Too cheap not to

 

[JohnSand]

But the hop tea also works. I've done it. Hopping is an art anyway, but I used math. If you are worried about dilution, add some extract too.