Author Topic: Starter boils over in the autoclave. Is there a fix?  (Read 3088 times)

Offline NicoleJS

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 5
  • BeerSmith 2 Rocks!
Starter boils over in the autoclave. Is there a fix?
« on: September 24, 2016, 01:24:39 AM »
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. tono de llamada gratis: https://descargartonos.info/

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!)

« Last Edit: June 07, 2020, 12:56:30 AM by NicoleJS »

Offline brewfun

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 2292
  • Malt dust is just alcohol's glitter
Re: Starter boils over in the autoclave. Is there a fix?
« Reply #1 on: September 24, 2016, 08:17:54 AM »
Part of the issue is that the autoclave super heats the wort, under pressure and in a moist environment. This decreases the ability of steam to release before it hits equilibrium with the environment. The result is a rather rapid change of state between liquid & gas. Great for sterilization, not so good for neatness.

The flask is contributing by having a narrow vent, making it even harder for gas to escape. A beaker might be helpful.

One technique to try is a quick (15 minute) preboil and chill. Separating the resulting wort from the break material will help reduce surface tension and nucleation sites.

You should try some foam control. You may need a generous amount, since it emulsifies and precipitates out. This will break surface tension and allow heat and steam to release more efficiently. 
Beer Appreciation is the space between pints.

Offline flars

  • BeerSmith Brewer
  • ***
  • Posts: 31
  • BeerSmith 2 Rocks!
Re: Starter boils over in the autoclave. Is there a fix?
« Reply #2 on: September 24, 2016, 02:58:10 PM »
Your starter wort doesn't need to be sterilized just sanitary.  Bring your volume of water for the starter to a boil in a kettle.  Boil for about 3 minutes to sanitize the kettle.  Remove the kettle from the heat and stir in the DME.  Recover the kettle.  After the wort has cooled pour it into the flask and pitch the yeast.  Any infectious material in the DME will be killed at pasteurization temperature of 165°F.