IBU

[craigb12]

I wonder if anyone can give me a bit of a blurb on international bitterness units (at least, i think that's what IBU stands for).

 

What's the normal IBU for say, a lager, or a stout, or an ale?

 

And some people on here, particularly in the recipe section, seem to be pretty good at working out what the final bitterness will be after dry hopping/the addition of various malt extracts: how do you go about calculating this?

 

I'm thinking that simple sugars will have no baring on the bitterness, but malt extracts will lower it? Maybe dark extracts lower it more than light ones?

 

I dunno...

 

thanks

C

[LeonardC2]

There are software programs available on-line to do calculations,like beersmith. You plug in what you used & how much,& it'll tell you IBU's,SRM,etc.

[PB2]

IBU is a measure of the amount of isomerised Alpha Acid (mg) per litre. The majority of the brewing world measures beer colour in EBC.

 

FAQ on calculating estimated bitterness and colour.

 

Dry hopping won't add bitterness to the brew. Bitterness comes from the isomerised Alpha Acid - isomerisation is achieved by boiling or steeping the hops in very hot fluid.

 

Bitterness is offset (or masked) by the residual sugars from the malt extract, it is not actually reduced by adding more malt extract.

 

The BJCP style guidelines are a good reference for expected bitterness per style. Lagers are often in the low 20s, Ales in the high 20s to 30s and Stouts in the 30s to 40s but there are many examples not conforming to this.

 

The bitterness of a finished beer will decrease over time in the bottle - this goes some way to explain why older beer tends to taste sweeter.

[craigb12]

That's great Paul thanks for clearing that up.

 

But it has, as all good learning does, inspired another question.

 

You said that the bitterness in a beer comes from boiling the hops to produced isomerised Alpha acid; that's interesting, because i'd always assumed that some of the bitterness came from boiling the wart (and not just the hops).

 

Here's the question: would you still be able to make good tasting beer by, say, buying a can of coopers malt extract (the unhopped stuff), adding it to the fermenter without boiling it, boiling hops for an hour or so on the stove, then adding the hop tea to the unboiled malt extract?

 

Would this work? Obviously you wouldn't get hot break occuring, which means that the proteins will not break out of solution, but is this really a massive problem? Maybe it would mean that your beer would be hazy. I dunno...

 

This is great... I feel like i'm learning so much about the whole brewing process these days.

 

Thanks Paul

[PB2]

Bitterness is normally produced during the boil but only because of the presence of hops.

 

Hot break occurs when the sweet wort gets going as a rolling boil in the brewhouse. There is no need to boil Coopers extracts (link).

 

Yes, you could boil hops separately and add them as a hop tea. However, the amount of bitterness extracted in this manner is likely to be more per gram of hops.