IBU loss and fermentation

[Noetikon]

I am wondering if people have any experience in preventing loss of IBUs during fermentation?

My typical experience is to lose considerable IBUs from wort to finished beer. For example, my last IPA was hopped with 2.5 oz of Chinook @ 60 minutes, then an additional 5-6 oz. of an Amarillo/Simcoe/Mosiac blend @ 10 minutes and flameout (steeped for 30 minutes). All straight pellets, no hop bags. The wort was super bitter when I pitched the yeast, but after a rather active fermentation, the finished beer tasted nothing like that (probably half the perceived IBUs). In the Brew Strong episode with Tinseth, I remember him saying all calculations are for IBUs in *the wort* and that all bets are off when it comes to figuring out IBUs in the finished beer, especially because the loss during fermentation.

Anyone have tips or tricks, aside from overloading the kettle with hops, for getting IBUs to survive fermentation and into the finished beer?

[cdburg]

Are you concerned about a loss of bitterness, a loss of hop flavor, or both? Yeast will definitely lower the bitterness as they ferment the beer and then drop out of suspension. The oils and other chemicals from the hops are absorbed by the yeast and removed from the finished beer. If you want a more bitter beer, you'd need to add more hops (or extract) to get more IBUs in the beginning of the process. You'll then end up with more at the end of the process. If you want more flavor, more end of boil hops and/or additional dry hopping (after the yeast is done and drops is best, in my experience) can help add aroma and flavor.

Some breweries also carefully control their pitching rates to either simply avoid overpitching or purposely pitch on the low end of the spectrum (La Cumbre Brewing) to avoid stripping too much hop flavor from the finished beer.

Personally, I like a more flavorful and less bitter IPA, so I concentrate on the flameout hops with a hop stand, a hopback addition, and a two stage dry hop addition. Trying to avoid oxydation at all steps also helps to make a beer that stands up a bit longer.

[Noetikon]

It's straight back-of-the-palate bitterness that I'm losing. I have no trouble with hop flavour. The last IPA I brewed had calculated 150+ IBUs at 60 minutes, but most was lost during fermentation.

Over-pitching might be the problem. I definitely over-pitched this last brew and lost a bunch of yeast from blow-off (about 4 oz!). So I'll try to avoid over-pitching and see if that helps.

[EagleDude]

some of your perceived IBU loss may be due to tasting wort with hop pellet particles still in solution and then tastin the beer once they have all settled out.

[cdburg]

I've found these tips from Vinnie Cilurzo on "making better hoppy beers" to be very helpful over the years also. Might give you more things to consider...

http://www.brew-monkey.com/articles/Bet ... _Beers.pdf

[Noetikon]

I've found these tips from Vinnie Cilurzo on "making better hoppy beers" to be very helpful over the years also. Might give you more things to consider...

http://www.brew-monkey.com/articles/Bet ... _Beers.pdf

Very interesting! Reading the replies here, I'm suspecting the cause is over-pitching. Though I'm not sure about the whole 'yeast strain' point. Why not a fast flocculator?? I prefer WLP007, so this is disheartening.

[peas_and_corn]

Flocculation is affected by surface charge on the yeast cell, and it is this that also causes the yeast to bind with alpha acids. As a result lower flocculators will absorb less acids.

[cdburg]

I've found these tips from Vinnie Cilurzo on "making better hoppy beers" to be very helpful over the years also. Might give you more things to consider...

http://www.brew-monkey.com/articles/Bet ... _Beers.pdf

Very interesting! Reading the replies here, I'm suspecting the cause is over-pitching. Though I'm not sure about the whole 'yeast strain' point. Why not a fast flocculator?? I prefer WLP007, so this is disheartening.

This document is a bit old. I wonder if Vinnie has changed his mind at all about English yeast. Firestone, after all, makes fine IPAs with English ale yeast. If you like English ale yeast in IPAs, I wouldn't worry too much about changing it. English strains do drop like a rock, which makes the dry hop more effective. You just need to be sure to get rid of diacetyl and dry the beer out. I think it's easier to do those things with Cal Ale, but if you can also do them with an Engliah strain. As long as you also make sure the esters don't clash with the American hops, you should be fine.