I bought some kimchi a few weeks ago, ate half the jar, and then forgot about it. I found it in my fridge yesterday and tried it. It tastes the same, but there isn't a date stamped on the jar. Does it go bad or should it be fine since it's fermented/pickled?
Most Koreans won't eat kimchi if
a) the veggies have become significantly mushy
b) the juices taste 'sparkly', it's hard to describe this flavor exactly, but when you taste it, you'll know what I mean.
A year seems like a long time for opened kimchi to me, but I would just use my tastebuds to assess the above.
Kimchi is rotten cabbage. It's already bad :) Seriously though, if it isn't moldy, it's probably fine. If you have the kind in the jar that has a carbonated taste, and it's still carbonated, it's fine.
In every Korean kitchen I have encountered, everyone has been extremely particular in that clean utensils should be used when extracting the kimchee from the jar, being very careful not to contaminate the kimchee. I have been told on many occasions that contaminating the kimchee can shorten the shelf life of the kimchee and taint the flavor.
My family will begin eating the raw kimchee about a week after it has been bought fresh from the grocery, after one month (if it is still around) I use whats left, cooking it with various dishes.
The more salt that is added to the kimchee and the cooler the temp it is stored at, the slower it will ferment.
Seems to me everybody has a different 'sweet spot' when it comes to the duration of fermentation they feel produces the best flavor. But I have never heard anybody storing kimchee for a year, and believe traditionally it was kept in Korea from one growing season to the next, in clay pots, underground. I have never heard of someone getting sick from eating old kimchee, but it definitely turns, and that in my mind constitutes as "going bad"
"Bad" is a relative term for fermented pickles -- the whole point of the things is that they are a bit spoiled. It should get more sour/pricklier/funkier as time goes on and still be fine, but use your eyes and nose: if it gets stinky in some new and exciting way or looks strange, I'd avoid.
I made Napa Cabbage Kimchi about 2 and a half months ago and had two containers in the back of the fridge. One was half full in a plastic honey container and a full one. I was worried that it had spoiled by this time but when I tried it, it was delicious. I am not Korean but I have enjoyed really sour kimchi for a long time. I'm so stoked that I have another 1 liter ice cream pail of the stuff.
I don't think it can go bad, but the flavour profile does change over time with homemade kimchi. Usually once it's past a certain point my Korean friend will use it for flavouring soups and stews rather than eating it straight. So it's just up to your personal preference.
I make Kimchi for the local farmers market and have a good following. I made a batch one year ago and kept some in the fridge. I just sold that one-year-old batch and it was delicious. The flavor was more mellow and a little more complex. It's fine. They had not been opened, however. I've heard of excellent 3-year-old Kimchi, unopened and kept cool. I typically sell mine after a couple of weeks of fermentation (one week fermented unrefrigerated). Best to keep it in the large container it's made in. I tried jarring it during fermentation and it was too messy. Even with the lids on loose I had to burp them every day so they wouldn't ooze over the tops!Fermenting in a 5 gallon bucket works best for me, then putting in the jars.
When I make kimchi, I usually leave it in a dark, cool corner of my utility room for 1-2 months before we start to eat it. We usually eat half the batch (1L) at once, then refrigerate. The second half is usually gone in a few weeks.
Last night, however, we finished a batch that had been forgotten about and sat in the fridge for about 4 months. It tasted great, although the cabbage had lost some texture.
I say as long as it isn't moldy, its still good. I would probably throw it out after 6 months though, just so I could justify making a new batch.
The process where cabbage and other ingredients becomes kimchee is a fermentation and pickling process. While the "sour" taste of kimchee comes from vinegar produced, which means there probably would not be a danger due to bacterial contamination, that pickling and souring process will continue.
The kimchee might be safe to eat, but it might be very, very and excessively sour after a period of time.
So, "bad" depends on whether you mean "just as tasty as it was when I first ate it," or "safe to eat."
Even when it gets "too sour" bad, it's still usable for dishes like kimchee chigae (kimchee stew), even if it might be too sour for your tastes to eat on its own.
If it's really sour, it's unlikely to rot unless maybe from some extreme mold. However, I have once witnessed a kimchi that was several years old (somebody had stored it in her cellar), and it had actually chemically decayed, tasting somewhat like wax. Very interesting, but utterly unpalatable.
On another note, I noticed that my kimchi turns LESS sour after a while; does anybody have an explanation for this, preferably one that makes biological sense? :)