Hop bitterness vs. Roast bitterness

I, too, wonder this. I've gotten into a discussion about Founders Imperial Stout with a friend and whether or not it's roasty bitter or hop bitter (could be both, I suppose). I do think there is a distinct taste difference, and I maintain that FIS is not overtly hoppy.

Another related question: does roast bitterness play into IBU measurement?

 

No, and that's why IBUs don't tell the whole story. There are other factors that come into play with perceived bitterness such as contributions from the grains, final gravity, water chemistry, even the temperature you are drinkiing the beer at. IBU is simply a hop utilization calculation to determine how the alpha acids were isomerized (essentially dissolved or broken down) into their bittering compounds- this pretty much happens over time at the right temperature. If the IBUs are measured after the fact I believe that this is what is measured, but cannot say for sure on that part.

You can have a lot of hop bitterness in a beer with no real aroma or flavor contributions from the hops. As the hops are boiled those other compounds are 'boiled away', and all you are left with is the bitterness if they are put in early in the boil and no other hop additions are used.

 

Roast coffee beans have bitterness, so does roasted grains.

IBU is a measure of the isomorized Alpha Acid from the hops, so the answer is no.

 

Bitterness from a stout, to me, is a completely different flavor than hoppy bitterness. I think people who use Hoppy bitterness to describe a stout are just hop heads who can't discern the difference. - Not that this is a bad thing, as it took me quit some time to really be able to notice the nuances and such between the two.

 

Not arbitrary at all. Look up the ASBC procedure. Saying that it is the only thing that influences the perception of bitterness is where things go off course.

 

Rogues XS imperial stout had hop bitterness and I personally can tell the difference.

 

yes there is./ I think so anyway. The roast bitterness is deep in the roast flavor and quality of the roast. You can tell it's part of the malt. The malt is crisp, dry and has bitter roast flavors like coffee and bitter chocolate and the hop bitter even if ti comes seems like grass and herbal by comparison to the dry crisp grain of a bitter roast. Hop bitter balances malt sweetness usually so that's another way to tell. Hop bitter cuts the sweetness form malt and seems refreshing.

Roasted Malts (may be steeped or mashed)

These highly roasted malts contribute a coffee or burnt toast flavor to porters and stouts. Obviously these malts should be used in moderation. Some brewers recommend that they be added towards the end of the mash, claiming that this reduces the "acrid bite" that these malts can contribute.

Chocolate Malt 400L Used in small amounts for brown ale and extensively in porters and stouts, this malt has a bittersweet chocolate flavor, pleasant roast character and contributes a deep ruby black color.

Black Patent Malt 580L This is the blackest of the black. It must be used sparingly, generally less than a half pound per 5 gallons. It contributes a roasted charcoal flavor that can actually be quite unpleasant if used in excess. It is useful for contributing color and/or setting a "limit" on the sweetness of other beer styles using a lot of caramel malt; one or two ounces is useful for this purpose.

Roast Barley 550L This is not actually a malt, but highly roasted plain barley. It has a dry, distinct coffee taste and is the signature flavor of Stouts. It has less of a charcoal "bite" to it than does Black Patent.


From How to Brew by John Palmer. (insight to the bitter character of malt)