IBU's - The Human Taste Threshold?

[Wez]

This topic has come up in chat tonight so I thought it would be a good one to discuss.

Doing some very brief research I have seen that there are apparently limits to what IBU level us humans can detect, so is it worth brewing a >100IBU beer, is the boundary 200IBU?

There is beer out there with the name 1000IBU which devonhomebrew kindly linked for me.

I brewed a 120 ibu IPA - was I wasting my time or should I have gone for 220 IBU?

What do we think?

 

[Devonhomebrew]

Thanks for posting this WEZ hope we get some answers. :

 

[Aleman]

From the research I've read the lower limit for IBU is around 15 . . . Oddly enough this is a level that is used in Budweiser . . . makes me wonder what the levels are in things like Bud Lite etc. :lol:

Now Upper limit, this is determined by a couple of things

Firstly the solubility of alpha acids is limited . . the boil turns them into Iso alpha acids which are more soluble. . . .so the boil vigour and duration are important.

Secondly iso alpha acids are broken down during the boil the rate depends on the amount of iso alpha acids in solution plus boil vigour, calcium levels etc etc etc this means that there is a plateau reached where the rate of iso alpha acid destruction is matched by the rate of iso alpha acid production. Which is what you can see on this graph from Glen Tinseths hop page



Thirdly is the upper taste perception threshold of the human palate, now this does vary from person to person, but has generally agreed to be around the 90IBU mark.

Now a couple of questions, can we brew a 200 or even a 400IBU beer? (one of the Durden Park IPA recipes uses 4oz of hops per gallon) . . . Here I am going to say that it is unlikely that we will ever reach this theoretical level. All the formulas for calculating IBU are flawed in some way, and using them with this hop rate is taking them far outside the zone in which they are intended to be used. The other factor is that while iso alpha acids are more soluble than alpha acids there is still a maximum solubility level that again will be well under the 'calculated' level.

This does raise another question, if there is a 1000IBU beer out there how did they do it? If it is an actual 'measured' IBU value rather than a 'calculated' one then it's quite simple . . .They cheated and added neat, chemically derived, iso alpha acids following the boil (and in fact probably following fermentation as high levels of iso alpha acids affect the stickiness of the yeast membrane and they flocculate early) . . . How would it taste . . . Bitter . . . but probably no bitter than a Hardcore or even a punk or possibly a Marstons Old Empire . . . remember we are WAY over the maximum taste threshold.

Is it worth brewing a beer with a high level of theoretical IBU? I would say yes, if you like that sort of beer , Many other flavours and flavenoids are extracted from the hops as well as alpha acids, and these all contribute to the flavour and hop profile of the final beer. Taking the Durden Park beer I mentioned earlier, firstly remember that these beers were casked for a year before being sent over to India via the Cape of Good Hope. During that time the bitterness would have been reduced, and the other flavour compounds all married together and the beer would have matured. It is surprising the complexity of flavour you get in a beer consisting of just pale malt and high levels of goldings hops, for bittering only, when it has aged for two years. (The high hop rate acts as a preservative and anti oxidant remember). Aroma is restored by dry hopping. The problem I have with these highly hopped beers when drunk young is that they all taste the same a massive citrus resin hit that just masks any other flavours, and is irrelevant of the variety of hops used. That resin flavour coats the tongue really preventing anything else from being tasted at all. . . . Can you tell it's not a favourite style of mine :lol:

 

[Vossy1]

It is surprising the complexity of flavour you get in a beer consisting of just pale malt and high levels of goldings hops, for bittering only, when it has aged for two years. (The high hop rate acts as a preservative and anti oxidant remember). Aroma is restored by dry hopping. The problem I have with these highly hopped beers when drunk young is that they all taste the same a massive citrus resin hit that just masks any other flavours, and is irrelevant of the variety of hops used. That resin flavour coats the tongue really preventing anything else from being tasted at all. .

Spot on. One of the most interesting things a home brewer can do is to make a high AA beer and then sample it through maturation to a level they no longer like. The perceived taste differences over this time are massive, from the mouth puckering inception to the smooth complexity of a fully matured brew. I used to get ribbed for my high IBU to OG ratios than the norm....oh how they missed out :grin: :drink:

 

[Scorrie]

Surely the bottom line is that 'numbers' are immaterial when it comes to taste and preference?

An arbitary scientific line is fine for calculations, but realistically, isn't it down to what the consumer likes?


(Posted after 6 bottles of Fyne Ales 'Highlander' : )

 

[Good Ed]

As an aside I was just listening to the Jamil show on http://thebrewingnetwork.com, an archive about Oktoberfest, and they were talking about IBU's and people's perception and taste, and were saying that if you have say brewed a beer at 35IBU but want to make the next one a bit more bitter, work in 5IBU intervals, because most people wouldn't taste the difference between 30IBU and 32IBU. I think I'm turning into a bit of a :geek:

 

[Aleman]

Actually that is a good idea because the majority of people can't distinguish between 30 and 35, around 5IBU difference is the limit that the 'average' palate can distinguish between two samples.

 

[evanvine]

Why bother with the brewing process, just drink Hop tea!

 

[Darcey]

Very interesting given the current demand/supply of cask/young 'IPA' style beers?!