Pitching Yeast and Wort Temperature for Kits

[Newts]

Hi All,

This may seem like a beginners question but I'm reading a few different things and I was hoping for a definitive answer.

When mixing a kit, starting with a certain amount of boiled water and the LME and adding the cold water to the specified volume the kit says that this is the most important time to pitch the yeast as long as the temperature is between 21-32 degrees. Just wanted to know why this is? Is there any reason you couldn't put the wort in a fridge to cool it to ideal temp then pitch the yeast to ensure fermentation temp is correct from the start. The other way I'm thinking is to put it in an ice bath with a sanitized temp probe in the wort and wait until ideal temperature before pitching yeast. I find that it's difficult to achieve ideal pitch temp with a hot/cold water mix from the start. I did read on one site the wort is susceptible to infection at the pitching stage but there was no reason why this is so.

Cheers,

Newts

 

[wbosher]

Why not chill a few liters of water the night before, and use these to top up fermenter?

 

[mikec]

Two main reasons.

1. Yes the longer you leave it the more susceptible you are to infection.
2. As you are mixing it all in you are aerating the wort. This is good for the yeast initially. The longer you leave it, the less "aerated" it will be. So if you do leave it for a while, give it a good vigorous stir (insert sanitation disclaimer here) just before pitching.

 

[wbosher]

What I used to do when brewing kits was to use a couple of litres of boiling water to mix the can of goop, DME etc, then top up to about the 20L mark with cold water from the tap, then check temp. If pretty close to the 20 degree mark, top up to 23L with tap water. If too warm use some chilled water, if too cold, use hot.

Also, don't pitch yeast anywhere near 32 degrees! Kit yeast is pretty forgiving but that is just crazy ****. Try to get it as close to the 18-20 mark as you can, a little higher is fine but not too high.

I've left up to about 60 minutes before pitching yeast with no problems, that's mainly after the boil with AG though. Had to aerate it thoroughly first though. If everything is clean and sanitised, there's probably not too much of an issue.

 

[Black Devil Dog]

The idea of using ice to chill your wort is one that some people disagree with, but done properly I can't see a problem with it and you don't need to leave your brew sitting around waiting for some nasties to inhabit it, or pitch yeast into a hotter than ideal wort.

Boil the water first, sanitise your ice container and seal it in the freezer. It will bring your wort down to pitching temp in a few minutes.

 

[warra48]

Pitching and fermenting around the 18 to 20ºC mark is generally good advice, for an ale, whether kit, extract, or AG.
32ºC is way over the top, and that crappy instruction is written only to ensure fermentation with an underpitched kit yeast will take off. It certainly will not contribute to quality beer.

I brew AG, and use an immersion chiller. During the warmer months, I can't get it to drop below about 25ºC, so I drain my kettle without splashing into the fermenter. It goes into the fermentation fridge to cool overnight, and I usually aerate and pitch my yeast the next morning or later that night. Never caused a problem.
In winter, obviosuly I can chill to pitching temp before draining the kettle, and I can immediately aerate and pitch my yeast.

An overnight chill will be fine, so long as you apply the usual sanitation cautions.