Dropping The Temperature Once Fermentation Has Already Begun. Safe?

[Coxy]

I have just put on my first extract beer after doing kit + kilo for a couple of years.

Recipe is basic, just 2kg light DME with 250g steeped carapils and 800g dextrose, OG a bit high at 1052 but it's my first step past kit + kilo so not too concerned.
30g Perle hops 60 mins (just for bittering)
30g Saaz 30 mins
30g Saaz 15 mins

It started fermenting overnight after being put into the fermenter yesterday afternoon, but is currently sitting in a cupboard alongside a frozen softdrink bottle at 24 degrees.

From the article here: http://www.aussiehomebrewer.com/forum/inde...?showtopic=9233 it suggests that it should be at somewhere more like 18 degrees, and suggests some methods for doing this, such as wet towels and icepacks, or 100 can cooler (if one can be found).

Do you think it's important to try to get it down to 18 degrees, and is it safe to drop the temperature now that it has already begun fermenting, considering that the yeast (Safeale US-05) was pitched at slightly above room temp (~30)? I am concerned that the yeast won't be happy if I drop the temperature this late and may go dormant.

Forgive me if this topic has already been covered about a million times on this forum, this is my first post on here after spending about 6 hours reading AHB over the last few days.

 

[argon]

yep get it down to 18C asap... that's the sweet spot for US05. A couple of frozen bottles with a doonah over it or something like that should be good. Monitor the temp and adjust as necessary.

How long ago did you pitch the yeast?

 

[Coxy]

How long ago did you pitch the yeast?

Yeast was pitched at about 3pm yesterday (it's currently 10am), so 19hrs ago.

 

[mwd]

I would try to get that temperature down ASAP It is during the early stages of fermentation that yeast gives out the esters and other funky flavours that you want to avoid.
See how it goes it may all be good in the end it may not be your best beer but you will have learned plenty.

 

[Coxy]

Cheers for your advice everyone.

I've had it covered in wet towels with some frozen softdrink bottles resting against it for about 8 hours and the temperature has dropped to 22. I'm doubtful it will drop much further with the method I'm using. I went looking for a big cylindrical cooler (like the 100/75 can coolers spoken about in other posts) but couldn't find any at kmart or bunnings unfortunately.

I'll have to think about this more before I put on the next brew, as this summer isn't likely to get much cooler. I'm considering trying to source a 2nd hand wine chilling fridge which is big enough, as they have thermostats which have a range of 10-18C. Otherwise I could look into getting a spare old fridge and installing a different thermostat.

 

[Kieren]

Do be careful the yeast doesn't drop out, though. They don't like big temp changes particularly from 24 to 18, 6 deg C is a lot to a little yeast cell. i agree you should try and drop the temp but it may need rousing if you find the yeast activity slows. If the krausen starts dropping and/or SG readings stall then try swirling the fermenting to keep the yeast in suspension.

 

[waggastew]

I have just had my ebay fridgemate built so I am soon to be free of ice bottles.....yippee!

For my previous batches though I used the 100 can cooler and it worked well. I also used a block of ice made in an old 2L icecream container. Tipped in boiling H2O, let it cool with the lid on, put in the freezer. Chuck it into the fermentor when you are filling up with H2O. Never had problems with infection.