yeast starter cold crash temps

[CompassBrewing]

At what temp do most of you like to cold crash your starters at? I ran a search and it seems like most go for around 35-40 but i just did one at 35 and it turned my 2l starter into a thick slushy. How cold can yeast tolerate?

 

[seabass07]

What ever my fridge is at. IMO, the colder the better without anything freezing. How did if start to freeze at 35?

 

[emjay]

Compass... what are you using to cold crash? A fridge? A chest freezer with a temp controller? How do you know what temperature you're chilling to?

What ever my fridge is at. IMO, the colder the better without anything freezing. How did if start to freeze at 35?

There's no way it froze at 35. It shouldn't even freeze at 32. The fault clearly lies with either the temperature measurement or control.

 

[CompassBrewing]

I put the starter in my kegerator (sadly it was empty....) and set my johnson temp controler to 35 with a dif setting of 3 degrees. I sanitized the sensor and immersed it directly into the starter.
I was extremely surprised to find the top half of the layer of my erlenmeyer flask frozen over-it took a few minutes at room temp to even realize it was just the top half as initially it looked like it was all one solid block
After my initial post I had a few brews and said screw it

Here's to hoping for a decent fermentation

 

[seabass07]

If the bottom wasnt frozen you should be fine.

 

[Kurisu]

I put the starter in my kegerator (sadly it was empty....) and set my johnson temp controler to 35 with a dif setting of 3 degrees. I sanitized the sensor and immersed it directly into the starter.
I was extremely surprised to find the top half of the layer of my erlenmeyer flask frozen over-it took a few minutes at room temp to even realize it was just the top half as initially it looked like it was all one solid block
After my initial post I had a few brews and said screw it

Here's to hoping for a decent fermentation

How did it work out?

This is a good lesson for the future -- temperature probes should always just measure ambient temperature. Use the controller's delay function and range function to keep the ambient temp +- 3 degrees of your target temp (or more or less depending on your purpose and how often you're comfortable with cycling your cooler).

If you immerse your probe in liquid, a starter, whatever, all that will do is insulate your probe from the ambient temp and cause the refrigerator/freezer to swing wildly +- your target.

Stuff I've learned from HBT and logic.

 

[CompassBrewing]

How did it work out?

This is a good lesson for the future -- temperature probes should always just measure ambient temperature. Use the controller's delay function and range function to keep the ambient temp +- 3 degrees of your target temp (or more or less depending on your purpose and how often you're comfortable with cycling your cooler).

If you immerse your probe in liquid, a starter, whatever, all that will do is insulate your probe from the ambient temp and cause the refrigerator/freezer to swing wildly +- your target.

Stuff I've learned from HBT and logic.

Luckily it resulted in a fantastic brew

 

[spenghali]

Is it a bad idea to put your starter in the freezer for an hour or so to jump start the temperature change?

 

[emjay]

Is it a bad idea to put your starter in the freezer for an hour or so to jump start the temperature change?

Not going to kill all your yeast, but I wouldn't do it... the slower temperature drop allows it to build greater trehalose reserves. In fact, even when the goal is to *freeze* the yeast (e.g. when banking yeast), it's best to cool it in the fridge first.