90 minute boil necessary?

[chthon]

I did a check on my own brewing spreadsheet, where I implemented the Tinseth model. Indeed, when going from a 60 minute boil to a 30 minute boil, one would only need appr. 1/3 extra hops to reach the same bittering level.

On the other hand, last year I did brew a couple of small volume, fast brew beers with 30 minute boils, and my perception was that they definitely were not bitter enough. Do not forget that Glenn Tinseth disclaims any accuracy on his calculation, except for his own setup.

Further experiences also would seem to indicate (not only from me, but also from other brewers on other forums), that a > 50 minute boil gives more or less the correct IBUs for the hops added at that time, while subsequent additions (30 minutes and less) give much less IBUs than the Tinseth calculations would indicate.

 

[The Baron]

I split the difference years ago and do 45 mins as it saves a little on brew day tim e and I just add slightly less sparge water than I used to compensate for the lack of boil off etc.

 

[Cwrw666]

Unless you boil your kettle dry, the temperature at the bottom of the vessel will always be around 100°C, maybe a bit more because of the sugars, but certainly not 10° higher.

The bottom of your kettle will be considerably higher than 100c. The wort obviously won't exceed 100c but sugars in the wort are in contact with the element/kettle bottom. Which presumably is why your wort darkens the longer it is boiled.

 

[Sadfield]

The bottom of your kettle will be considerably higher than 100c. The wort obviously won't exceed 100c but sugars in the wort are in contact with the element/kettle bottom. Which presumably is why your wort darkens the longer it is boiled.

True. And, with most cooking processes, colour equals flavour. Whether that flavour is desired is another question. One of the reasons for a vigorous boil is it decrease the temperature differential (ΔΤ) between the heat source and wort in order to avoid fouling. I think there's enough anecdotal evidence of scorched element/kettles on forums to support this.

To the original question, it's a case of determining if Proper Job presents those flavours associated with caramelisation and maillard reactions and adjusting your process on your own kit accordingly. I suspect for most homebrew setups a vigorous 60 minute boil would be sufficient.

 

[dmtaylor]

I did a check on my own brewing spreadsheet, where I implemented the Tinseth model. Indeed, when going from a 60 minute boil to a 30 minute boil, one would only need appr. 1/3 extra hops to reach the same bittering level.

On the other hand, last year I did brew a couple of small volume, fast brew beers with 30 minute boils, and my perception was that they definitely were not bitter enough. Do not forget that Glenn Tinseth disclaims any accuracy on his calculation, except for his own setup.

Further experiences also would seem to indicate (not only from me, but also from other brewers on other forums), that a > 50 minute boil gives more or less the correct IBUs for the hops added at that time, while subsequent additions (30 minutes and less) give much less IBUs than the Tinseth calculations would indicate.

The factor to consider here is the chill rate. Tinseth used a cold water bath, not an immersion chiller. No one ever says this or asks what method the OP is using to chill his wort after the boil.

 

[chthon]

The factor to consider here is the chill rate. Tinseth used a cold water bath, not an immersion chiller. No one ever says this or asks what method the OP is using to chill his wort after the boil.

Interesting. Actually, for these small brews (4 litre or so, 12 bottles) I also used a water bath, in the kitchen sink. Of course with a kettle of 10 litre, I can keep a whole lot of water, relative to the kettle, and augmented by ice cubes, it probably drops very fast under 80° C.

 

[tigertim]

or asks what method the OP is using to chill his wort after the boil.

I use the standard CF chiller which comes with the Grainfather G30. In the end, just kept to the instructions and followed them to the letter with the 90 minute boil. Following a very vigorous fermentation with Nottingham yeast (maintained at 17C with the chilled water regularly cutting in to keep it there) it finished at 1.012 giving me about 5.6%. And I concur that this is pretty much a carbon copy of Proper Job - an excellent clone!

 

[CaptAwol]

When I was doing a boil with the 'all in one' systems, I'd set the timer/program for a 75 min boil my opinion being that when reaching the boil it seemed to take about 15 min to get a constant rolling boil, but that's just me and my mad ideas.
Presently I'm brewing raw ale without the boil and getting brilliant results, for bittering I use Isohop oil which I add to the fermenter.

 

[Cwrw666]

For what it's worth:
My last brew was a pilsner. My usual practice is to boil for 60 minutes and then do the 15 minute hop addition - so 75 minutes total boil time.
This time however I cut it down to 30 minutes followed by 15 minutes, so 45 minutes in total.
I've just started drinking the first bottles and as far as I can tell it's indistinguishable from previous brews.

 

[The Baron]

I have done 45 minutes for years and just add a little less sparge water to compensate for the slightly less boil off. I too have not noticed any difference in fact as we speak I have just done a 35 min boil this morning as I have no hop additions just a whirlpool addition.
A overnight mash then a sparge and boil from 6.45 and the boil is done and cleaned up ready for the whirlpool when it has cooled by 8.30am.
Win Win in my world

 

[thunderfingers]

60 or 30 minutes is all you need.