Crash Cooling/Hot Water Cupboard?

[Tim Burnell]

Hello, first post... Tim from West Auckland here, good day to you

I'm kit brewing and have been adding additional hops through a boil and moving soon into grain brewing.
I've recently created a fermentation chamber using a stc-1000 and an old fisher and paykel upright freezer, happy with the setup.

My questions are that now I can ferment at a constant temperature and crash cool beer in fermenter once fermentation is complete...

A) when should I crash cool? ( I usually leave brew for 3 weeks in primary, should I just crash cool for a couple of weeks once fermentation is complete?)

B) once bottled should I put the (crashed cooled) bottled beer in the hot water cupboard for a week (as has been suggested to me with using extract kits) before moving to an under house cupboard? Or is this a little extreme now I'm crash cooling?

C) any ideas where I should place the heat pad in the fermentation chamber? (Maybe not under the fermenter???)

Look forward to some wisdom, cheers!

[Samuel Loader]

Hi Tim, 

You you want as a minimum the primary fermentation to be complete before crashing. I personally wait a week into the secondary fermentation before I do a diacetyl rest and then I start lowering the temperature, which I do at 3 degrees a day until I reach 3-4 degrees. I do this because fast cooling causes stress to the yeast and any stress to the yeast can cause off flavours to be produced (which may not be reabsorbed by the yeast). I have moved on to kegging now but when I was bottling I would bottle with sugar, allow the bottles to naturally come up to room temperature again (again for the reason mentioned above) If room temp is below the original fermentation temp now place in your fermentation box at the yeasts recommended fermentation temp for 48H then I would place these in just a dark cupboard for a couple of weeks before placing in the fridge ready for serving.

Note: with this method there really is a minimal amount of yeast carried over from primary- secondary- bottling. so heavier beers I tended to pitch a little bit of yeast into my priming sugar bucket to ensure carbonation.

Hope this helps   

[Tim Burnell]

Great info, thanks Sam. I like the idea of reaching crash cool temp slowly a lot and bringing bottles to correct temp via the fermentation box is an excellent idea, I'm a bit dubious that the hot water cupboard may cause off flavours by getting too warm after being nice and cold.

[Tim Burnell]

Another question for you. I'm making a lager at the moment and fermenting at 10.7C. Using 2x 11g yeasts. When is the best time to start the diiacetyl rest, I know it's meant to be a couple of days before fermentation complete but how long would a lager normally take to ferment?

[Ryan Perkins]

Hi Tim,

I have only done a couple of lagers so far but I timed the D rest by the appearance of the krausen.  Wait till it peaks and then let it fall back to point to maybe a third of its height before slowly raising the temp.  This may not be the best method but there was no traces of diacetyl in the finished beer.

You could also do a gravity reading but because I use carboys I don't usually bother.

[Tim Burnell]

Ok cool, thanks Ryan.

[Samuel Loader]

Ryans advice is good I follow a similar method called the Tasty larger method which works on SG rather than sight for primary ferment and diacetyl rest:

I pitch and oxygenate wort at 12C and hold until the gravity drops 50% of the way to terminal gravity

I then raise the fermentation temperature by 4 degrees to 19C and hold until the gravity drops 90% of the way to terminal gravity.

I then raise the fermentation temperature by 4 degrees to 23C and hold until I reach terminal gravity.

With this method, 75% of the fermentation takes place at 15 or below, 90% at 17 or below.

[Tim Burnell]

Hey Sam, this info is great but maths slightly out; did you maybe miss a step?
This sounds like a logical, great method. Stoked on the info you guys have given me.

[Samuel Loader]

maybe I did do this off the top of my head at work here it the original info if you want to work it out 

I pitch and oxygenate at 55F and hold until the gravity drops 50% of the way to terminal gravity (For example, if my OG is 1.052 and I expect to finish at about 1.010, then a drop of .021 gravity points would be 50%.) 

I then raise the fermentation temperature by 3 degrees to 58F and hold until the gravity drops 75% of the way to terminal gravity. 

I then raise the fermentation temperature by 4 degrees to 62F and hold until the gravity drops 90% of the way to terminal gravity.

I then raise the fermentation temperature by 4 degrees to 66F and hold until I reach terminal gravity.

With this method, 75% of the fermentation takes place at 58F or below, 90% at 62F or below. 

[Tim Burnell]

Thanks heaps Sam. Had a bit if a taste today and it's coming along good, used 15gram of hallertau hops as finishers and have got a great black currant result out of it

[Samuel Loader]

Awesome, happy to help. I need to hurry up and finish my brew sculpture so I can get back to brewing.  

[Peter Smith]

this is a good read, somewhere i have a link to a video from kai

accelerated pilsner brewing

http://braukaiser.com/wiki/index.php?title=Fermenting_Lagers

[Tim Burnell]

Ace read, though a lot of info to get me head around. Thanks Peter.