I've read several threads here (from as far back as 2008) discussing whether hop tea can successfully be used to add bitterness to a finished beer. I couldn't really get a good answer from any of them. Many suggested that it wasn't possible to add more than 5 IBUs to a 20-liter/5 gal from a 1-liter/quart hop tea addition. Some others suggested that it is possible, and one guy suggested that up to 40 IBUs could be added without significantly diluting the beer.
I'm posting this because I've just tried it and wanted to provide feedback for others. The answer is yes. A hop tea addition to a finished beer can substantially increase the bitterness of a finished beer without significantly diluting it. I estimate that you can add up to 15 IBUs to a 20-liter/5 gal with a 1-liter/quart hop tea addition.
I recently brewed a German lager with only 30g (a touch more than 1oz) of Hallertau Mittelfruh (3.2% AA) hops as an experiment to see if I could maximize the malt flavor of the beer. It worked, but the beer was almost sickeningly sweet. Online IBU calculators put the IBUs at about 12. I was considering throwing it out, but won't have a replacement for it for several weeks, so I decided to try to save it with a hop tea addition.
I had some extra Nelson Sauvin (11.2% AA) lying around that I wasn't going to use. It's not at all to style, but it was high AA and I had it, so I used it. I boiled 28g (1oz) of it in 2 liters of water (in a hop spider in a small saucepan) for 45 minutes. I drained it, strained it through some cheese cloth, and let it sit until cool. I tasted a tiny bit, and it was horribly bitter. The total volume of hop tea after boiling was 1.5 liters.
Considering how many people said that no more than 5 IBUs could be added to a 20-liter/5 gal. batch with a 1-liter/quart hop tea addition, I nearly dumped the whole thing into my beer, but I'm glad I didn't. I added half (0.75 liters/quarts), and it was almost too much. I have no way to test it so can't prove it, but I have little doubt that I've nearly doubled the IBUs in this beer from 12 to about 20-24. My best guess is that I added about 10 IBUs with my 0.75-liter/quart hop tea addition, which makes it about 13 IBUs per liter.
To be honest, I'm not quite sure how this is possible. Everything I've read says that the maximum IBUs in a given volume of water is 100 IBU. One liter of 100 IBU hop tea in a 20 liter batch of beer gives a 5 IBU increase. I got more than that... quite a bit more. I know because the last beer I brewed was the same recipe, but with 66% more hops (50g instead of 30g), giving me estimated IBUs of about 17. That beer was noticeably less bitter than this "fixed" one.
The beer was previously sickeningly sweet and undrinkable. It's now fixed and quite drinkable, although a bit more bitter than I was expecting. The hop tea was very hazy, so the beer is now a bit cloudy, but I suspect that will drop out over time. Also, the aroma of the Nelson Sauvin is quite noticeable and not to style, so if I was to do this again, I would use a style-appropriate variety of hops.
I'm posting this because I've just tried it and wanted to provide feedback for others. The answer is yes. A hop tea addition to a finished beer can substantially increase the bitterness of a finished beer without significantly diluting it. I estimate that you can add up to 15 IBUs to a 20-liter/5 gal with a 1-liter/quart hop tea addition.
I recently brewed a German lager with only 30g (a touch more than 1oz) of Hallertau Mittelfruh (3.2% AA) hops as an experiment to see if I could maximize the malt flavor of the beer. It worked, but the beer was almost sickeningly sweet. Online IBU calculators put the IBUs at about 12. I was considering throwing it out, but won't have a replacement for it for several weeks, so I decided to try to save it with a hop tea addition.
I had some extra Nelson Sauvin (11.2% AA) lying around that I wasn't going to use. It's not at all to style, but it was high AA and I had it, so I used it. I boiled 28g (1oz) of it in 2 liters of water (in a hop spider in a small saucepan) for 45 minutes. I drained it, strained it through some cheese cloth, and let it sit until cool. I tasted a tiny bit, and it was horribly bitter. The total volume of hop tea after boiling was 1.5 liters.
Considering how many people said that no more than 5 IBUs could be added to a 20-liter/5 gal. batch with a 1-liter/quart hop tea addition, I nearly dumped the whole thing into my beer, but I'm glad I didn't. I added half (0.75 liters/quarts), and it was almost too much. I have no way to test it so can't prove it, but I have little doubt that I've nearly doubled the IBUs in this beer from 12 to about 20-24. My best guess is that I added about 10 IBUs with my 0.75-liter/quart hop tea addition, which makes it about 13 IBUs per liter.
To be honest, I'm not quite sure how this is possible. Everything I've read says that the maximum IBUs in a given volume of water is 100 IBU. One liter of 100 IBU hop tea in a 20 liter batch of beer gives a 5 IBU increase. I got more than that... quite a bit more. I know because the last beer I brewed was the same recipe, but with 66% more hops (50g instead of 30g), giving me estimated IBUs of about 17. That beer was noticeably less bitter than this "fixed" one.
The beer was previously sickeningly sweet and undrinkable. It's now fixed and quite drinkable, although a bit more bitter than I was expecting. The hop tea was very hazy, so the beer is now a bit cloudy, but I suspect that will drop out over time. Also, the aroma of the Nelson Sauvin is quite noticeable and not to style, so if I was to do this again, I would use a style-appropriate variety of hops.
