making yogurt

[bensjen]

I've been making yogurt for a couple of years now, always using the same basic ingredients, equipment, technique. Last October, we moved into a new house, so I'm using a different stove. Ever since then, my yogurt is very runny. It still tastes like yogurt, and there is solid stuff in the bottom, and sometimes in the very middle, but for the most part, it's drinkable.

What's going wrong?

I can't think of anything different in the way I do it, except that the stove is different, but I use the same thermometer in the process, so the temps should all be the same. I've always filled a small cooler full of hot hot tap water and put the jars of new yogurt in there over night to get going. My cooler has got some cracks, I notice, around the top. Will this affect it's ability to retain the heat? I've tried refilling with hot water and letting the yogurt go longer, but it doesn't seem to make it much thicker.

[MamaTessa]

Do you check the temperature of the hot water, or just fill the cooler? Maybe the hot water heater at the new house is set lower, so you aren't keeping it in hot enough water?

[bensjen]

I thought of that, but the hot water here is hotter than at the old place.

Do you think the cracks along the top of the cooler affect it?

[tboroson]

Are you using the same milk? That could make a difference - the milk could be fresher or less fresh, or of generally different quality.

[bensjen]

I am using the same brand of milk, although lately I've been buying gallons instead of half gallons. The gallons do seem to expire sooner than half gallons. Does this mean that the half gallons are fresher? Would fresher milk make a difference? Next time I'll try getting a half gallon for the purpose of yogurt. THanks for the idea!