Cooking: How come no-bake cookies don't always set properly?

Last night I made some peanut butter & chocolate no-bake oatmeal cookies. This morning they are still fairly runny. Last week I made some and didn’t have a problem.

What keeps them from not setting properly? Anyway to fix this without making a new batch? I tried putting some in the refrigerator overnight, but those are also not firm either.

I don’t have a solution for you, but I’d certainly love your recipe.

In the name of research, of course.

Maybe an inaccurate measurement of a “wet” ingredient?

MMMMMM…peanut butter & chocolate…

Is it possible your 'fridge is fuller this week than it was last week? A full 'fridge doesn’t get as cold as an empty or nearly empty one.

Also, are they on the same shelf as they were the last time? I’m not sure if this is still true, but I always thought the coldest part of the 'fridge was the top shelf, in the back.

Well, I don’t actually put them in the fridge to set. I just leave them on the counter. But last night I put a few in the refrigerator just to see if there was a difference in the consistency of the two by morning. There wasn’t. One was warm goo and the other was cold goo.
Any other ideas?

The recipe:

(from allrecipes.com)

2 cups white sugar
3 tablespoons unsweetened cocoa powder
1/2 cup butter
1/2 cup milk
1 pinch salt
3 cups quick cooking oats
1/2 cup peanut butter
1 teaspoon vanilla extract

Directions

1 In a saucepan bring sugar, cocoa, margarine, milk, and salt to a rapid boil for 1 minute.
2 Add quick cooking oats, peanut butter, and vanilla mix well.
3 Working quickly drop by teaspoonfuls onto waxed paper and let cool.

What a coincidence – I made these very cookies last night. They set fine, too. I’m enjoying one as I type.

I see you only used 3 Tbs of cocoa – I used 1/2 cup. This could be the problem.

Sounds like the recipe I use except I add one cup of coconut and 1/2 cup of chopped peanuts on top of the peanut butter.

However, I melt the peanut butter along with the boiling concotion instead of adding it with the oats. If the heat from the mixture is going towards melting the peanut butter along with cooking the oats, it could affect the outcome of consistency.

It certainly could be a problem… but I used this exact recipe the week before and they turned out fine.

Mmmm…coconut.

Fatdave, this is a mystery! Did you cook the cocoa/sugar/butter mixture shorter or longer than usual? Did you use the same kind of peanut butter?

Even following the same recipe, some days things just don’t work out right.

My mom is nigh-famous for her peanut brittle. Every Christmas, she makes batch after batch and sends them out as gifts. But I remember well one day…she tried at least three times, but each time the sugary mixture just didn’t set properly. Instead of spreading out the way it should, it got all foamy, then stringy and clumpy, ending up as a discolored peanut mess.

I’m inclined to think that it was the humidity. Some days just weren’t meant for candy-makin’.

I’m going to have to go with humidity as well.

Hmmmm… Humidity for baking times… any experienced no-bake chefs here that know the difference in how these turn out if you cook the mixture too long, as opposed to too short?

I made these in Japan at a cooking class for kids using improvised ingredients. Well, they were the same ingredients but quality and type of food available at Japanese supermarkets differs from America, duh.

Everyone was using the same ingredients. However, my group didn’t get enough milk, cooked it too long, and was slow setting the cookies. Needless to say we had awesome cookie crumb crunch but very little was in the form of an actual cookie. The other groups all came out perfectly of course.