Some of my flavours are 9+ months old, nothing suggests that any of them have gone bad though. I'm just wondering if there is a best before time period with concentrates, I've heard that they don't necessarily go bad but just change. What have you found with your concentrates over time? Let me know!
I have some concentrates that are well over 2 years old, still perfectly fine. I find that the more air in the bottle the weaker they become but it's negligible. I just adjust accordingly.
Your flavors will not spoil in the same way as a salad left out in the afternoon sun... but you are right that the profile will change over time. This is not always a bad thing though (unless like you experienced, it ends up tasting like plastic). Some flavors mellow out and mature nicely with a little bit of time, just like a juice that needs to steep.
The worst flavors to store tend to be citruses which not only react with many materials, but also tend to loose their initial brilliance. I'd recommend moving some of these flavors to glass or PET if you are going to store them longer than 3 months. For instance, we stopped packaging our 4oz Lime flavor in HDPE because it destroyed the material.
Some other notes about long term storage:
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Keep your flavors out of the sun. Sunlight heats them and can break down the flavors.
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Unless the manufacturer says otherwise, store them at room temperature. Extreme temperatures, including cold, will cause separation.
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Eliminate the head space (air left in the container after use) or use an inert gas to back fill large containers for long periods of storage. This will prevent both reaction with oxegen and moisture from coming in which will change the color and consistency of your flavors.
Thanks for your detailed reply and the salad analogy!
I have only a few citrus flavours and I believe they are already in PET but I might be wrong. Always keep them at room temp and in the dark, not going to be messing around with gas though. Thanks again!
You won't really know until you mix with it. If they're really far gone, they won't smell as vibrant. But most of the time you'll notice the flavor isn't holding up after a few days. That's when you'll know you should replace. They don't like "spoil" or anything though, just aren't as potent.
Typically, from what I heard, it just starts either tasting bad or very weak. In rare cases, some flavorings can change color but it's uncommon. Most flavors are PG or alcohol based so they last a long time. I can't recall any of mine going bad and I've had some for a long while.
The only flavorings that I've noticed change color are some of my vanillas. They just became a bit more amber over time. That's why some commercial juices are yellow instead of clear. I'd expect my bottle of Bavarian Cream to get darker (since it's already a light amber color), but I haven't had it quite long enough to notice.
they do have a best before but not a use by. I think there is a legal requirement to have that best before, that's all. I bought from a local FA distributor and they sent some bottles that were past the best before date, they were free with explanation that they're still good but couldn't legally sell them.
https://en.wikipedia.org/wiki/Aroma_compound
I don't think you're going to have any real issues. Probably will just taste weaker over time. They're pretty much just made to be exactly like the version that occurs in nature, and with my limited chemistry knowledge I don't think they just break apart in any practical time frame unless you're doing something funny to them, like expose to serious heat, humidity, or just pour it out and expose it to the air for a long time.
Make sure you shake them up before you use them! If they taste funny, throw them out. Not sure you should worry about expiration beyond that.
As for natural flavors, those might react differently. They're usually less pure than artificial flavors from what I know, and that's probably a lot less predictable in how it reacts over time. I think the "toss it if it smells bad" is a pretty good general rule (for food too of course).
I know what they are supposed to smell like so i do the sniff test . Maybe two out of over 100 went bad on me over a two year period.
I'd be curious to know what they were. I have a 2 year old bottle of TFA Hazelnut that I believe has gone bad. I just can't stand it in any recipe anymore. Perhaps my taste has changed though. My solution was get FW Hazelnut and forgetaboutit.
Cotton Candy & FW regular bubble gum flavor.
I worry about the plastic. I went back to an old 140 plastic with a few ml's left in the bottom for a few months. It was terrible, seemed to taste like plastic. I have a few flavourings from early last year I wish I had transferred to glass.
I think HDPE can be problematic (it's that soft, milky-white stuff), although many of my bottles are over a year old and are fine. I do keep mine in a dark cupboard away from heat, though.
PET plastic (the harder clear stuff) is supposed to be less prone to that sort of chemical leeching, and TFA switched to PET bottles a few months back. I know part of the reason was that the HDPE ones sometimes leaked in transit, but I think the PET bottles are better anyway.
LDPE is softer than HDPE. HDPE feels a little softer than PET, but I only have two HDPE bottles. PET does seem to be better, and if you're ordering more, you can get them in amber, which should also help with degredation.
I stand corrected. Plastics aren't my forte, and I get LDPE and HDPE mixed up. I was referring to the one that TFA used up until recently, but now I don't know which it actually was. Either way, I think the PET bottles are better for storage, unless someone really wants to spend the time and money to transfer everything to amber glass bottles. That's a good idea for nic base, but for flavorings I think it's kinda overkill (also, I can think of way more things I'd rather spend money on ;) .)
Here is a useful reference on plastic permeability from Alpha Packaging