Why Does The Boil Foam Up When Adding Hops?

[peas_and_corn]

Just a curiosity- when adding hops, the wort foams up like crazy and I have to be careful to avoid a boil over. Why does this happen?

Cheers,

Dave

 

[jgriffin]

I've always assumed it's because the the hops give a rough surface allowing the formation of bubbles a lot easier.

Similar to adding sugar to superheated water

http://www.phys.unsw.edu.au/~jw/superheating.html

 

[warrenlw63]

P&K

Since I've been a "skum-skimmer" the instances of this happening seem to have lessened. If you're not sure what skum-skimming is, it's the process of scooping the foam of the surface off the wort just as it's coming (and about 2 mins. in) to the boil.

Also another advocated method (though I've never tried it) is to have a pump spray of water and to spray the surface of the wort with it when the potential boilover/foaming occurs.

As to why the hops cause this? Not totally sure. :unsure: Have heard something along the lines of the hops breaking the surface tension??

Warren -

 

[Tseay]

I suspect its because of the the hops moisture content. The water in the hops boils instantly when hitting the boiling wort.

 

[beersom]

The hops are forming a nucleation point for dissolved gasses to come out of solution.

 

[johnno]

It is an orgasmic lovein between hops and wort.

cheers
johnno

 

[Ross]

It is an orgasmic lovein between hops and wort.

[post="117164"][/post]​

:wub:

 

[Jye]

The hops are forming a nucleation point for dissolved gasses to come out of solution.

When you dry hop nucleation points form and gas is released from the beer. I agree with beersom that the same thing is happening in the boil but just much faster.

 

[Pumpy]

Dave ,

I have similar problem when I boil milk in a cup in the microwave then add the instant coffee , It all boils over the edge of the cup although it is outside the microvave .

Why is this so !!!!! :blink: :huh: :unsure:


Pumpy

 

[Trough Lolly]

Yep, I'm with the more nucleation points in the boiling wort thanks to the hop particles being added theory...

Cheers,
TL

 

[peas_and_corn]

hmm... that makes sense!

Cheers!

 

[Jazzafish]

I have similar problem when I boil milk in a cup in the microwave then add the instant coffee , It all boils over the edge of the cup although it is outside the microvave .

Why is this so !!!!!

If you boil distilled water, well heat it to 100*C, it doesn't bubble. However if you add anything to it at this temperature, it will boil over rapidly. Like an explosion. Which is basically a very fast reaction.

It is the impurities in the water that cause the bubbling. Adding hops to the boil will break surface tension and add impurities that react violently and escape as gass via the path of broken tension.

According to Myth Busters exploding water test. However, after seeing the clever show I have doubts in such programs! :lol: