Starter boils over in the autoclave. Is there a fix?

[Charlie]

My experience is that whenever I autoclave a starter I get boil over. The starters are exactly half the volume of their flask (e.g. 1L starter in a 2L flask). I have tried various things to overcome this:

1. Leave the prepared starter on the stir plate until gas quits evolving (takes approx 30 min).
2. Gently heat the starter before autoclaving.
3. Lower the temperature slowly upon completion of the sterilization cycle.

Nothing seems to work. I still get boilover in the autoclave. The typical result is that a 1L starter (2L flask) will be reduced by 75-150 ml, and a 2L starter (4L flask) will be reduced by about the same amount.

Is there a fix for this, or am I forever condemned to cleaning the equipment after sterilizing a starter? (please don't mention catch pans. that isn't a fix!)

TIA,
Charlie

[BDawg]

I just do them in mason jars in my pressure cooker. No muss, no fuss.

[Kbar]

So, Water at 15 Psi boils at 250F from what I have read. They call this the magic number for "complete" sterilization of beer spoiling organisms. Anyone find any issues doing it the Bdawg way of mason jars and just being submerged in boiling water (212F of course)??

[Charlie]

I use sterile mason jars all the time for rinsed yeast,no problem. And boiling a starter in a pot doesn't cause the boil over issue. I think that the problem occurs after the cycle is finished and presssure is dropping, but no matter how slowly I drop pressure I still get some boil over.

I used to make starters and slants by boiling in a pot, but a lot of my slants (~ 50%) would grow green mold. Autoclaving pretty much eliminated that, so I autoclave starters too.

[NateBrews]

I don't think Mr. Bdawg was advocating just boiling in mason jars, I think he was using mason jars in his pressure cooker to go up to 15PSI.

I don't have much experience with pressure cookers, but I did can a load of apple sauce for the first time in mason jars at 15PSI for 15 minutes and those boiled over quite a bit. In every pint jar I lost about 1" of material while the boiled ones were fine. So, I don't know.

Are you pre-cooking the wort so that it already has gone through the hot break cycle? I think I would want to do that first, then put it in the autoclave to sterilize. Otherwise you will get a boil over like you would if you just put it on the stove turned up to 11.

[Charlie]

Are you pre-cooking the wort so that it already has gone through the hot break cycle? I think I would want to do that first, then put it in the autoclave to sterilize. Otherwise you will get a boil over like you would if you just put it on the stove turned up to 11.

That sounds like something to try.

I'll boil the flask and starter in my stock pot and eyeball it periodically to see if it foams, then if/when it subsides I'll chunk it in the autoclave. Thanks!

Charlie

[NateBrews]

Are you doing this in an erlenmeyer flask, or some other "safe for the stove top" kind of glass? If you do, you could just put that on the stove and boil the wort in it (that is how I do my starter worts). I think you need to get the stuff up to boiling to get the hot break to happen, and if you have it in boiling water that probably isn't going to happen (since I think the sugar water boiling point is higher than regular water). If you don't have that, you could always boil it in a pan first and dump it in the flask before autoclaving it.

[BDawg]

I don't think Mr. Bdawg was advocating just boiling in mason jars, I think he was using mason jars in his pressure cooker to go up to 15PSI.

Exactly. I leave an little space, maybe 1/2" in a quart jar. Put on the flat lids and screw down the rings, hand tight but not overly so. Never have any problems.

It really is dangerous to can wort after only boiling it. While the probability of actually contracting botulinum spores is somewhat low, it doesn't matter. That shit can kill you. Don't mess around. Pressure cooker or don't do it.