Weirdness when using a flask to make a yeast starter

Ok, so this is some bizarreness that has now happened to me 4 times....I need some help good people of the interwebs!

I'm attempting to make a starter, and I clean and sanitize my Erlenmeyer flask. I'm using PBW and Star San at their recommended levels to clean/sanitize. Then I put in my water, start it boiling, then add the DME. As the DME is boiling it attempts (occasionally with success) to boil over. I use the back end of a wooden spoon (this time I used a kabob stick) to do some mild stirring and combat the boiling over. As it starts to settle, I notice a purplish (maybe light black?) tint to the foam. Its not just a small speck, its an area the size of your thumb, maybe larger.

My question is this. Has anyone else had this happen? Is it something I'm doing that I can prevent? Any thoughts? Ideas? Help

It's normal - the shape of the flask can really accelerate a boil over if you aren't careful.

I put 1600 ml of water in mine and I go ahead & add the DME when it's warmin up, then I remove from the heat and cover with foil as soon as it starts to boil. I'm only trying to sterilize the flask, not make a mini-batch.

I make starters needing 2L's.

I will heat about 1L in the flask.

In a pan of water I will warm .5 L's of water and dissolve my DME in that water. I then add this to my flask, top off as needed and bring to a boil to finish the process.

It isn't so much the boiling that I'm worried about. It is the purple/blackish that gets in the foam part. I can't for the life of me figure it out.

Probably burnt DME.

I use the boil half the water, add DME, then add cooled water technique. Works much better.

Try one drop of Fermcap in the flask. I do that and it doesn't foam up.

I can my starter wort so I don't have to boil in the flasks. Just pull it out of the pantry and pitch yeast and starter. A lot easier for me.

kapbrew13 said:

I can my starter wort so I don't have to boil in the flasks. Just pull it out of the pantry and pitch yeast and starter. A lot easier for me.

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Boiling in the flask is as much about sterilizing the flask as about sterlizing the starter.

tphjr said:

Boiling in the flask is as much about sterilizing the flask as about sterlizing the starter.

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That's cool. Everyone has their own methods.

Spartan1979 said:

Try one drop of Fermcap in the flask. I do that and it doesn't foam up.

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We have been using Fermcap for the last two starters and that has solved the boil over problem. We also stepped up to a 5L flask so we can make a large starter at one time. We have had two very successful brews using this method of making our starters.