IBUs, ABV and perceived bitterness

[UTDoug]

How does alcohol content impact perceived bitternes?

I just think its strange that Dogfish Head 90 min IPA is 90 IBUs and I love it, Stone IPA is in the 70s and I love it, and I had a celebration ale last night for the first time and at 60 some IBUs it was curl the sides of your tongue bitter to the point where it was unenjoyable.

SN could be really inconsistent and maybe I got a 100+ IBU batch, or does the higher alcohol content of the DfH 90 minute and the Stone IPA do a lot to tame the bitterness? I know the sweet maltiness does a lot for the 90 minute but I'm curious about the alcohol content.

Thanks,
Doug

 

[67coupe390]

I think it depends on the hops used too.

 

[Brewsmith]

It depends on the starting gravity. The more malt, the more hops you need to balance it out. 50 IBU's in an pale ale would be alot, but in a high gravity beer, it would be barely enough. Sierra Nevada's Celebration Ale is a normal strength IPA, while DFH 90 minute is an Imperial IPA, with a much higher starting gravity. Even though it has 90 IBU's, the perceived biterness isn't as much because of all of the malt sweetness.

 

[UTDoug]

So if I'm looking at recipes for IPAs, alcohol content isn't really a factor - just the malt or yeast attenuation % and the anticipated IBUs?

 

[Brewsmith]

Basically. A good way to judge is by making a ratio of bitterness units to gravity units or BU:GU. Most hoppy beers have a ratio of near 1. I've seen many IPA's that have around 60 IBU's and an OG of around 1.065. The ratio ends up being 60/65 or 0.92. Less hoppy beers, say an amber may have IBU's at 25 and an OG of 1.050 the ratio is 25/50 or 0.50. Lightly hopped beers can have a ratio of 0.33 or even less. Hefeweizens can have IBU's at about 15 and an OG of 1.048 giving a ratio of 15/48 or 0.31.

 

[zoebisch01]

When you look at the relationship between hop utilization and wort (boil) gravity they are sort of inversely related. So as gravity goes up, utilization goes down so two beers one at 1.074 and 1.045 (for example) using a single malt, same boil volume and same hop additions will be totally different in bitterness. From what I have read is that there is basically less 'room' in the higher gravity wort for the isomerized alpha acids.

Like Brewsmith notes, there are other fators that impact how you are percieving the bitterness. Malty and sweet characteristics can also influence your perception of said bitterness.

 

[Bobby_M]

What you say is true but IBU calculation already takes gravity into account. So, when you say a recipe is 90IBU, that's it, no matter how high OG is. As far as I know, all brewing software makes adjustments (I know even the simple Qbrew does it).

 

[david_42]

Also, there are six (or nine or 12 depending on how you count them) main bittering chemicals in hops, but IBU doesn't tell you which are providing the bitterness. Columbus can be really harsh in high concentrations, as can Chinook. Nugget has similar AA levels, but most people find it to be rather mild. The beta acids tend to get ignored, but they are very important in noble hops.

Homebrewing is a process of finding out what combinations you like the best.

"Compounds derived from hops determine the bitter taste of beer. Hops and hop extracts used in the wort boiling process contain three main alpha-acids (humulone, cohumulone, adhumulone) and three beta-acids (lupulone, colupulone, adlupulone). During wort boil, six iso-alpha-acids are formed from the three hop alpha-acids."

 

[zoebisch01]

What you say is true but IBU calculation already takes gravity into account. So, when you say a recipe is 90IBU, that's it, no matter how high OG is. As far as I know, all brewing software makes adjustments (I know even the simple Qbrew does it).

This is a good point. IBU by definition is a standarized form of bitterness which eliminates how we arrive at the conclusion. But, when brewing beer it can make a fairly big difference in your final product if your boil gravity is less than anticipated was what I was trying to point out (ie something to keep in mind all the time when brewing, or at least I pay close attention as I really don't like overly hoppiness for the most part.)

 

[zoebisch01]

Also, there are six (or nine or 12 depending on how you count them) main bittering chemicals in hops, but IBU doesn't tell you which are providing the bitterness. Columbus can be really harsh in high concentrations, as can Chinook. Nugget has similar AA levels, but most people find it to be rather mild. The beta acids tend to get ignored, but they are very important in noble hops.

In my short life of homebrewing thus far, I have already noticed there are huge differences from one combination to another. I really like Colombus as a bittering hop added in small amounts. Kind of fascinating really how even small changes in the hops additions can make big changes in the final product.

One more thing I was thinking about (in regards to the original post), and I am not sure how they do this commercially (I would guess they pull samples) but most hbs's list the AAU as a number say 14.1 but that in itself is not necessarily dead on. I would imagine with pellets/plugs (ie processed and blended etc) would give a more consistent number but more likely a range is in order. I mean really, unless you lab test every batch of hops addition your numbers could be off a bit (some of the hops ranges are very wide). Aside from a general familiarity with a particular hops variety, how does one go about making it dead-on? Just something I have wondered about lately. Most of this stuff just seems to be ball-park-ish (not that this a terrible thing, but it won't be exactly the same every single time.

 

[dcbrewmeister]

You're missing the most obvious answer - they all (according to the clone recipes anyway) use different hops. IBU's is just a number, it in no way tells you "what" it's going to taste like. Different hops add different flavors and aromas to a brew.

Read this article for more info.

 

[dcbrewmeister]

In my short life of homebrewing thus far, I have already noticed there are huge differences from one combination to another. I really like Colombus as a bittering hop added in small amounts. Kind of fascinating really how even small changes in the hops additions can make big changes in the final product.

One more thing I was thinking about (in regards to the original post), and I am not sure how they do this commercially (I would guess they pull samples) but most hbs's list the AAU as a number say 14.1 but that in itself is not necessarily dead on. I would imagine with pellets/plugs (ie processed and blended etc) would give a more consistent number but more likely a range is in order. I mean really, unless you lab test every batch of hops addition your numbers could be off a bit (some of the hops ranges are very wide). Aside from a general familiarity with a particular hops variety, how does one go about making it dead-on? Just something I have wondered about lately. Most of this stuff just seems to be ball-park-ish (not that this a terrible thing, but it won't be exactly the same every single time.

That's why you use the AAU numbers for your additions instead of hops weight. Using 1 once of XYZ hops with an AAU of 4.2% will give you a different taste/aroma than 1 once of XYZ hops with an AAU of say 6%.

In the world of hops, 1 once just means 1 once by weight, the AAU's may be completely different. You should base your recipes on AAU's and not weight.

 

[treehouse]

How does alcohol content impact perceived bitternes?

Thanks,
Doug

I noticed my wife seemed less bitter after a homebrew or two...

But seriously, scientifically I would think that alcohol would increase the perceived bitterness because it would dissolve the hop oils better. Just a theory. Also I think bitterness can be due to "yeast bite" which is different from hop bitterness and is a fault in beers. I know because I've brewed some it. That might be what is peeling the back of your throat.

 

[zoebisch01]

That's why you use the AAU numbers for your additions instead of hops weight. Using 1 once of XYZ hops with an AAU of 4.2% will give you a different taste/aroma than 1 once of XYZ hops with an AAU of say 6%.

In the world of hops, 1 once just means 1 once by weight, the AAU's may be completely different. You should base your recipes on AAU's and not weight.

The point I was making is, 1 oz of say Colombus may have a range of AA per oz. F'instance my LHBS has a number of 14.1 (as memory serves) for Colombus. That is 14.1 AAU's of bitterness per oz. You can easily find it slightly higher (or lower depending on where you look) from different suppliers. Here are two random examples:

http://www.sfbrewcraft.com/looseleaf.html# 15.4 AAU (Colombus)
http://www.northernbrewer.com/hops.html 10-12% AA per oz. (Colombus)

Yes, it is standardized so that you are looking at per oz, but all that is simply done is multiplying the percentage AA by 1 oz.

From the two examples you really are looking at a range (between the two suppliers from as low as 10% AA per oz or 10 AAU (standard for 1 oz) up to as high as 15.4 AAU (standard for 1 oz). That is a significant difference for the same strain of hops.

To drive home my point, lets say you purchase from Northern Brewer. Your final bitterness for a batch could vary from:

28 (60 minute @ 5 gal of 1.06) (10%AA)
to
34 (60 minute @ 5 gal of 1.06) (12%AA)

and if we use the other site

43 (60 minute @ 5 gal of 1.06) (15.4%AA)

with 1 oz addition. Those are significant differences. Of course this can simply be splitting hairs if the range is small, but the first and last example are not. So the long and short of it is, you are correct but I was making a different point that even the same strain of hops can be vastly different in terms of bittering potential. The aroma and flavor characteristics that (its profile) would be close or the same, but it's power to impart bitterness from the Alpha's is different.

 

[dcbrewmeister]

zoebisch01 - I thought I was agreeing with you:rockin: Common mistake with new brewers is a recipe calls for 1 oz of XYZ hops @ 6% AAU, so they buy 1oz of XYZ hops @ (whatever AAU 'cus we didn't even look) and throw it in.

Then the question comes up "my brew doesn't seem "hoppy" enough"

My point was don't get too awfully hung up on the weight of an addition, pay more attention to the AAU's the recipe calls for. AAU's will vary wildly from suppler to supplier for the same hops.

LHBS store packages them in 1oz packages ' cuz they buy them in bulk and break it down, not to make it easier fot you to brew.

 

[zoebisch01]

zoebisch01 - I thought I was agreeing with you:rockin: Common mistake with new brewers is a recipe calls for 1 oz of XYZ hops @ 6% AAU, so they buy 1oz of XYZ hops @ (whatever AAU 'cus we didn't even look) and throw it in.

Then the question comes up "my brew doesn't seem "hoppy" enough"

My point was don't get too awfully hung up on the weight of an addition, pay more attention to the AAU's the recipe calls for. AAU's will vary wildly from suppler to supplier for the same hops.

LHBS store packages them in 1oz packages ' cuz they buy them in bulk and break it down, not to make it easier fot you to brew.

ROFLMAO, doh sorry! I just wanted to clarify my point. Hopefully it didn't come across like the Grand Inquisition or something . This is basically my same point....Colombus aint Colombus aint Colombus, if you know what I mean.

 

[UTDoug]

Thanks for the input - I'm realizing this hop balancing game is a lot more complicated that it seems. It seems like its basically luck as to how you approach the delicate bitter/too bitter threashold. Even when you know the AA % for the batch the ounces you used might be more/less potent, something about how the beer was brewed could cause more/less extraction, almost anything can throw off a brew. I think thats why you can go to the local pub and have a pint of a new IPA and its the best one you've ever had, and next week its a new keg and its too bitter, and the week after that its even better than the first time.

Here's to an exciting game of chance going on in my fermenter right now!

 

[david_42]

but that in itself is not necessarily dead on.

Actually the AA % on a packet of hops is dead on, for that packet. Hops vary so much year-to-year that each crop has to be tested. It varies from farm to farm within a region and even from field to field. And this is for growers that fertilize and irrigate to minimize the changes. If hops are processed into pellets or plugs, they will have a different AA% from the whole hops. Generally a little higher.

That's the big reason people don't recommend using home-grown hops for bittering. The flavor and aroma oils are much more consistent.

All said and done, most people can't spot a 10 IBU change in bittering and once a brew is at 80-100 IBU, your taste buds hit the wall.

 

[dcbrewmeister]

After it's all said and done - the original question was about three different brews with different taste (as far as the hops flavor) and the simple answer is the different hops used to make the brews.

The IBU's of a micro-brew, brewpub, or recipe that you yourself brew is, for the most part, just a number. The type of hops, when added to the boil, and how long in the biol is the real deciding factor for taste.

Obviously a beer that has an IBU of 100 compared to a beer that has an IBU of 30 will have the greater hop flavor. Not all beers with an IBU of 100 will taste the same unless made with the same hops and the same method of additions.

You must learn to balance flavor and aroma in a brew. I love my IPA (that reminds me, time to brew it again) but most people don't like it due the intense hop flavor. I like hoppy beers though, but thats just me.

 

[zoebisch01]

Actually the AA % on a packet of hops is dead on, for that packet. Hops vary so much year-to-year that each crop has to be tested. It varies from farm to farm within a region and even from field to field. And this is for growers that fertilize and irrigate to minimize the changes. If hops are processed into pellets or plugs, they will have a different AA% from the whole hops. Generally a little higher.

That's the big reason people don't recommend using home-grown hops for bittering. The flavor and aroma oils are much more consistent.

All said and done, most people can't spot a 10 IBU change in bittering and once a brew is at 80-100 IBU, your taste buds hit the wall.

Well that's kind of what I wonder in general, because you could even have sections of a crop (within a crop, generally speaking here) that are superior or inferior. So do they just take random samples, or how does this work? As for the commercial brewers I would imagine they constantly take samples.

 

[zoebisch01]

I think thats why you can go to the local pub and have a pint of a new IPA and its the best one you've ever had, and next week its a new keg and its too bitter, and the week after that its even better than the first time.

I think there is greater volatility in smaller scales. Large scale brewers have certain luxuries that the local brew pub does not. It takes a great deal of care, attention and understanding of the whole process to hit it every time (and not everyone does this anyway %100 of the time).

You know, I just tried Rogue's Mocha Porter last night for the first time. The website lists it @ 54 IBU, darned if I would have guessed it. I am beginning to wonder if a new scale for bitterness isn't in order which accounts for these other elements. It seems to me, thinking on this now that IBU really doesn't tell you much except approximately how much Alpha Acid has been utilized in the beer.

 

[dcbrewmeister]

I think there is greater volatility in smaller scales. Large scale brewers have certain luxuries that the local brew pub does not.

Correct - Large scale breweries make 5-6 batches at a time of the same beer (let's just call it bud light), ferment it, lager it a bit (not long, if at all), filter, blend, bottle and keg. obviously not step-by-step, but a lot of blending goes on at the big boys. Most brewpubs just don't have the tank space to do it. Not to mention that most brewpubs only have one brewing setup.