I don't think they necessarily go bad, but they are susceptible to cross contamination. Especially if you aren't using a new syringe with each flavor. TFA is the only vendor I know that seems to do this as well. One day my juice is perfect, mix a batch a few months later with the same concentrates, and it has a funky ass rotten foot smell (after exhaling it). The most notorious seems to be TFA honey, but a few others do this too. Just have to be very careful and make sure you minimize cross contaminating your concentrates. They'll taste fine, but you're wife will get super pissed because she smells feet, even though you're on the other side of the house.

I keep my mixing room and supplies pretty pristine. Eliminating most of my TFA flavors seemed to correct the issue.

I've never had any issues with tfa flavors. Some of those oldest are probably 6+months old.

I made a mix with strawberry ripe that smelled and tasted rotten. But I used the same bottle in other mixes and they didn't smell or taste rotten. Are you sure it's not the recipe? I haven't had any other tfa flavors taste like they've gone bad. I've had them taste bad, but it had to do with my mixing, not necessarily the flavors themselves.

i talked to linda at TFA. She said that strawberry ripe and other fruits will change when left in plastic that breathes or is opened several times. She also explained how alcohol is detrimental to the flavoring as it actually carries flavor molecules away. About custard notes like Diacetyl Acetoin and Acetyl propionyl titanium dioxide Sodium arsenate. Nobody has actually done testing on how safe they are to inhale especially in the long term so she advises to tell customers or label your products with 'vape at your own risk.'

I think I know what you mean by smelling rotten. I bought some banana cream from them and made a single flavor mix with it. It tasted great the first few weeks but after that it tasted like a rotten banana or something really bad.

it's not the recipe . I've been using these concentrates for at least 6 months. I like the refrigerate idea.

and there's no cross contamination. I used new mixing hardware to make a single flavor green apple for testing. TFA gladly sent out a replacement telling me they personally inspected it.

Sounds like you just got a bad bulk batch. It happens occasionally.

I recently received a bad batch of FA Bilberry, but it's my first flavor I've received that was bad. It was ok for about 2 weeks, but then turned absolutely rank. No cross contamination and no weird storage, just an AC'd closet.

I'll be buying a cheap mini-fridge in the coming weeks I hope (if the wife will let me) to start storing all of my flavors in. I've heard it helps.

I've also noticed, at least for some of the smaller flavor drams from RTS Vapes and Wizard Labs that the caps aren't necessarily providing an air tite seal. A long exposure to the air could contaminate them (long meaning 3+ weeks.

Lately, I've started rebottling all of my flavors as I order them anyways so that I can mix by weight, rather than leaving them in silly non-air tight drams that make shit go bad.

Edit: I've also started to label all of my flavors with the dates they were received on and from what supplier so I at least remember who to go back to if I have a problem within a few weeks.

I have used ripe strawberry that is almost a year old. Tasted weaker, but not spoiled.