Gravity and bitterness units

[guypettigrew]

Somehow I feel there should be a relationship between the gravity of a beer and the IBUs.

But I can't see one! Do we taste IBU levels the same regardless of gravity? In other words, would a 45 IBU ale have the same bitterness effect in our mouths in a 3.5% beer and in a 5.5% beer--for example?

Looking at Graham Wheeler's mild recipes (it's that time of year again!) I see his Boddingtons mild, at an OG of 1.032 has 24 IBUs. His Gale's festival mild, at 1.054, also has 24 IBUs!

I've just brewed a series of pale ales at increasing IBUs. At 50 or just over, the ale is really bitter, even though the wort started at about 1.052. Not too bitter to drink, though! I'm thinking of settling on about 35 IBUs. Whatever gravity ale I brew, this seems to give me the right level of bitterness.

Is this why Graham's mild recipes all sit at around 20-25 IBUs?

Anyone have any idea about IBUs, please.

Guy

[shredder]

You've probably seen this before but it might be worth a read if not:

http://beersmith.com/blog/2009/09/26/ba ... ess-ratio/

I actually use this value more than I should I expect but I find it helps me get what I'm after for different styles. In a typical ale I'll usually go for a value of 0.6-0.8 depending on if I'm brewing an IPA, or standard bitter or whatever. Hope this helps.

[Kev888]

I use the BU:OG ratio too. As a relative figure when I'm trying to tweak a recipe without significantly changing the balance, or as a guide to the balance when I am purposely trying to change it, then its an easy way to keep a rough check on how things are altering. Its in this roll that I do find it pretty useful.

As an absolute figure though, I only really use it to check how my recipe compares to the generally accepted territory for the typical style, though that doesn't mean I always follow it. If I'm purposely aiming for something to more specific tastes (say mine) and/or less normal for the style its not something to be restricted by IMHO.

There are times when it can be misleading, as well. I find it less helpful in heavily hopped brews where the relationship seems to break down, bitterness perception isn't linear and people can drink stuff that has ridiculous looking BU:OG ratios. Conversely a typical BU:OG (by itself) doesn't mean it 'will' be good; you could imagine for example adding a shed-load of hop extract to a tin of barely diluted LME to get a perfectly normal looking ratio - probably wouldn't win many awards though. And the ratio is only about bitterness, saying little of flavour - if the bitterness is simply a shed load of high alpha hops at 90mins then it could be perceived as far less nice and in fact less well balanced than if it were exactly the same bitterness (and so BU:OG) in a recipe using many more later hops giving a more rounded, less stark flavour

Cheers
Kev

[shredder]

+1 to all that Kev has said for sure. Especially regarding more heavily hopped beers and only being about bitterness relationship and not flavour.

[newtonsshed]

Also doesn't sweetness bring out the bitterness more too? Like adding sugar to coffee, the more crystal malt used the more the preceived bitterness.

[Patterd Ale]

Not being argumentative but, I have always thought that sweetness required more bitterness to balance it out. For example my RIS at 8.5% has over 100 IBU's and isn't really at all bitter. My session ale at 4.2 has 32 odd IBU's and equally isn't really bitter. My imperial IPA at 8.5 has 90 odd IBU's isn't bitter enough.
Cheers, PA

[Beer O'Clock]

This might be of interest. It's been on here a few times now but could be worth repeating...

[super_simian]

I find Balance Value a better indicator than BU:GU, because it takes into account the effect of attenuation. Drier beers will seem more bitter, and BV takes that into account.

http://www.tc.umn.edu/~rohw0009/homebre ... bvcalc.htm

[shredder]

Yeh I find BV is a really good way of quantifying perceived bitterness as a function of how dry/sweet the finished beer will be so I probably use it more when I brew something like an Imperial IPA (as noted in that link) that has a different FG compared to the usual styles I brew. I use BrewMate which gives you both values so it's easy to quickly check if you're in the ballpark of what you want, I haven't used many other programs but I expect they will also have these built in?

[CRoark]

check out the most recent Beersmith Podcast http://beersmith.com/blog/2013/04/25/ho ... odcast-58/ where Brad talks to Dr Charles Bamforth about bitterness which touches on this subject.

[guypettigrew]

Nice graph, Mr Beer o'Clock, thanks!

I've snipped it and printed it out.

Guy

[barney]

Guy,

I had a similar problem a while ago and then one day I noticed that an awful lot of good recipes, particularly Pale Ales and Bitters had an IBU level which was the difference between the starting gravity and the finishing gravity. I tried it and wow what a difference in the beers, everything just seems in balance, Perfect for my palate anyway. Give it a shot. You wont be disappointed.

[darkonnis]

I think its important t opoint out a few things here:
IBUs is a very theoretical value.
-There where some studies done by homebrewtalk which show that going over about 50IBUS is pretty difficult. They found that if you throw 1kg (exmaple) of whatever hop in for an hour, the resulting brew will have plenty of hop taste but likely not be that bitter as the AA boils off as they approach the liquid saturation point(they are of course quite volatile) (the same study found that hop acids from a brew approachign 130IBUS where found in the bottom of the bottle.

-The other thing ot bear in mind is utilisation factors, the chances of those being 100% is pretty damn slim though pellets are better than whole hops because of the increased surface area.

Not to rain on anyones parade here or anything but I think those points get left out and that they are definitely worth considering.

Back on topic:
I too thought that BU:OG was usually as a ratio, but that you also needed to bear in mind what flavours you want to come through, ie a mild probably doesn't want to be full of hops but more malt and a touch of bitterness and an IPA doesn't want a monsterous malt bill which leaves any hops quaking in their cones.

Cooky

[guypettigrew]

Excellent points, Cooky.

So it seems as though about 50 IBUs is the most a wort can hold. You're saying anything much over this just boils off?

That's good news. Means I shan't bother trying a 60 or 70 IBU brew.

However, as my taste buds tell me 50 IBUs is too much for the approx 5% ales I usually brew, it's all a bit academic.

About 35 IBUs seems right for me, so I now need to work out how to get loads of hop flavour but keep the bitterness down. Late additions etc is probably the way forward, but I'll have to try a few brews to see how it goes.

Oh dear, this research is so tiresome!!!

Guy

[koomber]

Slightly off topic, but another thread mentioned using a 'hop puree' to get better dry hopping from hop flowers/leaf. Do you think there would be any issues with using a similar process to get better utilisation?