Fermentation Support Forum

Hi everyone

I have been fermenting yoghurt with powdered milk and lacto starter sachets. Mix powder with cold war in a plastic container which goes inside plastic insulating vessel filled with boiling water.

I've been having a freak-out about plastic and food recently though:

http://www.motherjones.com/environment/ ... stic-safe/

So I tried the same process with a glass container inside the plastic insulating vessel filled with boiling water. No go. Glass container has the same volume so ratios are the same. Must be a temperature thing. Then I tried mixing the powder with water (between 115F/46C-110F-43C) and placing in a bath of the same temperature - again, no luck.

Any ideas?

I don't quite understand your setup and the role of the boiling water, but if it works in the plastic vessel and not the glass, but guess is the increased thermal mass of the glass. I'd try preheating the glass up to around 110F and then doing it just like you did with the plastic and see if that does it.

Hi Chris

Thanks for your reply.

My set up is two vessels: one is the actual fermenting vessel that contains the mixture, the other is the incubating vessel. The fermenting vessel is placed into the incubating vessel which has been filled with boiling water. Both are these vessels are plastic. I am wanting to replace the plastic fermentation vessel with a glass jar

I thought perhaps that it was the opposite problem, that it was too hot since glass conducts heats. But I'm definitely going to give your suggestion a shot.

Thanks,
Josh

Hi Chris

You were right - I needed to raise the internal temperature. So I mixed the lactobac-milk mixture with water with a temperature of 115F/46C-110F-43C in a preheated glass jar, and this went inside a thermos with boiling water.

Worked twice in a row now, so the method is confirmed I reckon.

Thank you,
Josh

Great news! Glass has a whole lot more mass than common plastics.