one way to help keep your simple syrup from going funky is to add a teaspoon of vodka or other neutral alcohol to the syrup.

I also stored mine in the fridge, but it still would get cloudy/nasty. Instead, I keep it in the freezer in a tupperware-type container. It freezes up to a thick slushy consistency and I spoon out what I need. No moldy bits. :-)

Oh--no worries--if you've read other foodpickle posts of mine, you'll recognize this as my mantra. It comes from very hard experience--I made beef stew once and let it sit out a little too long. It wasn't fun. I did some research after that about food safety and I'm in the "better safe than sorry" camp.

Thank you drbabs - I don't use it often but I made some lavender infused (strained) syrup for lemonade this summer. I guess I didn't want to throw out my home- grown lavender goodness, but I was being lazy and maybe unsafe! Thank you innoabrd, you're right sugar is cheap and not worth the risk. I RETRACT MY LAST COMMENT!

If in doubt, throw it out!! @Sadassa_Ulna, you may be able to kill the bacteria, but you can't get rid of the toxins they have produced. Why get sick? As innoabrd said, sugar is cheap. Throw it out and make some more. (And keep it in the refrigerator.)

it isn't all that dissimilar to the stuff they use to culture organisms when they're trying to see if you have strep...sugar is cheap, why risk it?

I keep mine in a lidded glass jar on the counter, and if it has been a while I stick it in the microwave (lid off). This is not very scientific but I like to think that if I get it really hot I am killing off the botulism. I have a rich imagination ;)

I've got a batch I made last spring and it's find. And I never refrigerate simple syrup.

I've done that before and what's curious about it is that one time it was fine for at least a week and another time, thin strands of bacteria were evident after only 3 days. I'm not sure what the reason is, but that being said, I've had good luck with it for about 4 weeks when kept in the fridge.