The problem with old legumes of any kind is that a) they cause much more gas than fresh ones, and b) particularly with beans larger than lentils, they don't soften no matter how much you cook them. I'd say throw out those lentils and get some new ones.

Why risk it?

I don't know, "musty" sounds like mold to me. I once rinsed some lentils, then didn't end up using them so after they seemed "dry" I poured them back in the jar and into the cupboard. A week later I discovered them fuzzy with mold! Ew. Perhaps the writer's peas/lentils had gotten slightly damp and grown a little mold. I personally wouldn't risk eating anything that smelled musty.

The letter doen't even state if the soup was refrigerated or at what temperature. Once food becomes mushy and wet it's more likely to attract bacteria. I'd toss that stuff out. Next time try freezing the leftovers.

We just cleaned out my grandparents' cupboards, where most of the food hasn't been touched for 3+ years since my grandma had a stroke. She had tons of beans and lentils, which I took just in case. Some of the beans did smell musty and I threw those away. Others I felt weird about, wondering if they would soften, so I ended up using them as pie weights. I'll have to report back on the other ones if I end up trying to cook them.

I think boiling lentils that could be moldy would kill the mold... but then again, my nose is hyper sensitive to anything musty or smelling like mildew so I probably just wouldn't use them and save myself the grief. They are cheap enough... sad to waste food but, eh.

If the soup passes a taste test, I wouldn't give it another thought, assuming it has been stored properly since it was MADE LAST WEEK. Dried beans have an indefinite shelf life. Personally, they all have [what some might describe as] a musty smell to me but, but then I have a very sensitive sense of smell and I *expect* them to smell that way.

In the end, it all boils down to that with which you are comfortable. If the thought of a taste test fills you with fear, then by all means, dump the soup. It's not worth the stress. Life's too short.

Thanks everyone! I'm the one who asked the question. Just to clarify, I emailed the question the day I made the soup and someone from thekitchn answered me right away. So, the soup hadn't been sitting for awhile before I wondered about it.

I didn't notice mold or any strange smells with the dried lentils and peas, but i think it was after they had soaked in water for a bit that they started to smell. I just didn't realize that's what the smell was until after the soup had been cooking.

I did eat it (and froze half) and it was delicious. No ill after effects, except for confirming adameran's insight that they do cause more gas!

No fear, good for you! And thanksomuch for the feedback. Lol @ the fuel exhaust.

I was just asking myself that same question tonight - I threw my old lentils out - I've had them for about a year, and whilst I made a batch about 3 weeks ago, they took too long to cook, and I felt uncomfortable eating it...

Next time..make bean bags.