Effect of temp difference at time of pitching?

[sergiov]

Hi all,

brewing here in Chicago (back when it was cold!), there were a couple batches I accidentally chilled down under 60F with my immersion chiller, with my yeast sitting at room temperature (was using single wyeast packs for 2.5gal batches).

Despite the 10F+ difference, I usually would just go ahead and pitch rather than risk an infection by waiting for them to equalize temps. Fermentation started up fine within 24 hours or so...

So my question is -- how close in temp do you typically try to stay when pitching? Is pitching warmer yeast into a cooler wort harmful to the yeast? How about the reverse? Should I have stuck the yeast into the fridge for a bit before pitching?

Thanks...

 

[MalFet]

With abrupt temperature drops, yeast prepare to go dormant. That's not really what you want at the start of fermentation. The general consensus among the yeast-gods seems to be that pitching colder yeast into warmer wort is neutral to good, but pitching warmer yeast into colder wort is generally not a great idea.

 

[sergiov]

ok - got it... make sure the yeast is colder than the wort... thanks!