I was looking for my little jar of Marmite the other day and couldn’t find it. ‘Someone’ has a habit of tossing things that are well beyond their expiry date. She says she doesn’t remember throwing it out, but I’ve been warned. (I told her Vegemite and Marmite never expire!)
That’s when she mentioned having tossed an unopened jar of almond butter that was in the cupboard. For various reasons (one of which is that I tend to buy large jars of peanut butter), I never got to eating it. It was past its ‘best by’ date by about a year, so it got thrown away. (I did turn it occasionally to allow the oil to circulate.)
If it’s anything like peanut butter, it should be good well beyond it’s legally-mandated “Use by” or “Best by” date. If it’s bad, it would probably be rancid, and you could easily tell.
I’ve found almond butter will go rancid in hot weather, much faster than peanut butter (but maybe I was just unlucky), so I would be careful tasting a year-old jar.
As noted above, almond butter can go rancid. On the other hand, it sounds like you never opened it, so a factory-sealed jar ought to last nearly forever. Once it’s open and the air gets in, it won’t last long, even in the fridge.