what's the difference...

[PD]

between a 60 min boil and a 90min boil.

and don't say 30 mins !

I'm not a lover of overly hoppy beers so I think I can get my required hoppiness from a 60 min one. So what other benefit will a 90 min boil give me, being a Yorkshire man I'm thinking of saving 30 mins worth of electricity !... :party:

 

[graysalchemy]

Using a 90 minute boil you will fix more of the Alpha acids out of the bittering hops so in theory you will use less, also secures the hot break better. I always do a 90 min boil. :thumb:

Oh and the difference is 30 mins in my calculations but I could be wrong :rofl: :rofl:

 

[alanywiseman.]

28 mins................no wait GA is right it is 30 mins :rofl:

 

[joe1002]

Oh and the difference is 30 mins in my calculations but I could be wrong :rofl: :rofl:

:rofl: :rofl:

 

[graysalchemy]

It is actually all to do with Time and Space Complexity




First, we show that in certain situations there can be large gaps between complexity classes.
Theorem 3.1 For every computable function f : IN ! IN there are monotonically increasing
functions

s; t : IN ! IN with
DSPACE(s(n)) = DSPACE(f(s(n)) and
DTIME(t(n)) = DTIME(f(t(n))) :

The theorem implies that there are functions t; s with
DSPACE(s(n)) = DSPACE(22s(n)) and

DTIME(t(n)) = DTIME(22t(n))

At ¯rst glance, this seems to be quite surprising. However, it has been shown, for instance, that
DSPACE(o(log log n)) = DSPACE(1), which explains why such gaps can occur. We will see
that for \well behaved" functions s and t it is not possible to create such gaps.
Another phenomenon is that it is quite easy to achieve constant improvements in space or
time.

Theorem 3.2 If L can be decided by an s(n) space-bounded Turing machine, then L can be
also decided by an s(n)=2 space-bounded Turing machine.

Proof. Let M be any s(n) space-bounded Turing machine that decides L, and let ¡ be the
tape alphabet of M. In order to obtain an s(n)=2 space-bounded Turing machine for L, simply
extend the alphabet by ¡ £ ¡. This will allow to encode two cells of M in one cell and therefore
to reduce the space requirement by a factor of two.

Theorem 3.3 If L can be decided by a t(n) time-bounded Turing machine, then L can be also
decided by an n + t(n)=2 time-bounded Turing machine.
Proof. The proof will be an assignment.


I could go on more but then I may be accused of talking complete and utter B*llocks

:lol: :lol:

 

[joe1002]

:shock: :wha:

I'm lost.

 

[graysalchemy]

Do you want me to explain again

:rofl: :rofl:

 

[Aleman]

I think the basic premise of theorem 2.3 is based on a fallacy . . .there is a tautological argument in there somewhere.

The Correct Answer is obviously 1E

 

[Aleman]

Actually I have just recalculated and a closer result is 36

My apologies for my earlier mistake

 

[PD]

well I understood GA's post up to the word First.

Your all crazy ........

I think your all missing the point of casuality being involved, whereby time is relative to the actions being undertaken. i.e where something pleasurable seems to last 2 mins whereas 5 mins in the dentist chair would seem like a lifetime.
Therefore 30 mins saved on a boiling could relate to a 5 min love making session ( ha ! ) or an afternoon spent with your in laws. It depends on your point of view.

However you have failed as yet to convince a yorkshireman on the benefits of wasting oodles and oodles of leccy which would certainly be more than the cost of a few bittering hops.

 

[Swift Pint]

if you're using pilsner malt then a longer boil is more beneficial.... something to do with boiling off DMS pre-cursors, bad flavours etc or something... not sure of the science thought. :wha:

 

[Aleman]

Well I've abandoned my search for a proper job and just come back into the lab so I can answer this question.

Boiling wort essentially serves 3 (perhaps 4) purposes which are time related.

1) Isomeration of the hop alpha acids . . . which makes wort bitter
2) Sterilisation of the wort
3) Reduction of protien, through heat degradation.
4) Drives off unwanted volatiles

Extraction of bitterness is related to the amount of hops, how much alpha acid they contain, and, duration of the boil. If you reduce one of these, say boil duration, you have to increase either one or other of the two factors . . . most easily by increasing the quantity of hops. There are several formula that you can use to determine thins adn they are incorporated into most brewing software.

Sterilisation of the wort is achieved by a boil of 15-20 minutes, so all worts should be boiled for a minimum of 20 minutes. . . . even kits technically.

Unwanted volatiles can be driven off quite easily. The one the US brewers all seem to worry about (DMS) does not exist in British malts as it is taken care of in malting, so a 60 minute boil is adequate to drive off any left behind following malting. Foreign malts may be higher in precursors so a longer boil may very well be desired.

The real factor that determines a 60 or 90, or longer) boil is getting rid of excessive protein.as the boil proceeds protein clumps together and the wort gets progressively clearer, eventually there comes a point where the wort does not clear any more and the protein clumps are about match head sized. This is the hot break, and generally never happens before 60 minutes . . . but more usually 90 minutes. I therefore prefer to say boil to secure the hot break, rather than giving a time to boil for. If you boil 'hard' then you can achieve the hot break sooner, but you have to then accept the issues that result from excessive thermal degradation of the wort, a more gentle rolling boil achieves the hot break after a little longer boil. For those especially pale beers wort is boiled at a 'simmer' and for 2 or three hours!!

 

[PD]

A superb answer, thank you very much indeed.

It will probably hurt a Yorkie but I guess a 90 min boil is called for.... :thumb:

What a great forum.

 

[fbsf]

... could relate to a 5 min love making session

3 Times? In the same day?

 

[enitharmon]

:shock: :wha:

I'm lost.

Don't worry, he's just a bloke thinking of his last pint. I think it may have had some funny mushrooms in it

 

[graysalchemy]

:shock: :wha:

I'm lost.

Don't worry, he's just a bloke thinking of his last pint. I think it may have had some funny mushrooms in it

Not at all and how dare you accuse me of taking drugs.

 

[Swift Pint]

... the issues that result from excessive thermal degradation of the wort, a more gentle rolling boil achieves the hot break after a little longer boil...

Sorry to distract you further from the job search, but could you ellaborate? I dont think I've heard of this thermal degredation before.
I always assumed that the hot break was what happened when all the foam appeared at the beginning of the boil, I guess not..!
Is the advantage of a good hot break to get a clearer wort & therefore clearer beer then? Any impact on flavour?
Do you reccommend a longer less vigerous boil to achieve a hot break then?

Cheers

 

[The Goatreich]

... the issues that result from excessive thermal degradation of the wort, a more gentle rolling boil achieves the hot break after a little longer boil...

I always assumed that the hot break was what happened when all the foam appeared at the beginning of the boil
s

That's what I thought too.

 

[Aleman]

[quote="Sparge Pervert":2ud38l4x]I always assumed that the hot break was what happened when all the foam appeared at the beginning of the boil

That's what I thought too.[/quote:2ud38l4x]
Ah, good old John Palmer :evil: . . . . . Blithering Idiot! :lol: :lol:

The only book in which I have seen the hot break described in that manner is JP's How to Brew . . . Particularly the online edition which I hate with a passion :twisted: :twisted:

Palmer calls the foam that forms as the wort comes to the boil the Hot Break . . it isn't, hot break forms after 60-90 minutes of the boil. This initial foam is composed of beta glucans, tannoids, proto-tannoids and the degradation products of said glucans (along with a few enzymes/proteins).

So what is the Hot Break, and When do we achieve it?

Boil a wort and during the boil take wineglass sized samples of wort every 15 minutes throughout the boil. Initially the samples are cloudy, but as the boil proceeds minute particles start to form . . . as time proceeds these particles get bigger and bigger and the wort clears, until they are about hatch head sized and there is no difference between successive samples. At this point you have achieved the 'Hot Break' and the wort should be visibly clear with more than a hint of sparkle.

 

[joe1002]

As always, a very helpful thread, thanks guys :