My office just got a case of Maxwell House instant coffee. As noted by my co-worker, the aroma of the coffee powder smells more like soy sauce than coffee, which most of the instant coffees we had.
The actual coffee tasted fine, the initial aroma was just offsetting. Is there any specific reason (maybe in the method of processing) for why the aroma of Maxwell House instant coffee powder smells this way?
Instant coffee is not generally considered to be the epitome of great tasting, or smelling coffee. It's almost the antithesis of artisanal whole bean arabica coffee.
The iconic and appealing smell of freshly roasted or brewing coffee is due to arabica coffee. Instant coffee though is mostly, and often completely, made from lower cost robusta beans. Robusta beans have a distinctly different taste and aroma profile.
And while industrial roasters have gotten very good at coaxing arabica-like flavours from instant coffee, the underlying qualities are still there and still noticed in the aroma. So the short answer is that your brand of instant coffee smells a lot more like typical robusta beans than the more desirable arabica beans.
Aroma is somewhat subjective and can be easily influenced by suggestion. I can understand your perception of soya sauce, although that characterization might be a bit off the mark. Soy sauce covers a large range but is something of an earthy umami aroma usually having malty seasoning, cooked potato, caramel, alcoholic, smoky or honey notes.
Myself I would describe the MH instant coffee aroma as bittersweet like the artificial sweetener, Sweet n low, sweet and bitter/metallic/alcohol aroma over a predominantly peanut and wet paper flavours.
I use Maxwell House instant coffee. It is freeze dried, which adds nothing to the coffee. I have an acute sense of smell, yet, I've never noticed an odd smell from the Maxwell House, only, a lack of smell. Then upon further examination, discovered the jar was near it's expiration date. My theory is, that since your group opened it and all noted the "soy" smell...but, then, the taste was normal. That something in your environment was contribbing to the scent, and the coffee in a different environment would have smelled normal.
It could be a combination of things. I often notice a "fishy" smell from any coffee I consider roasted too dark. While the taste is generally fine, I find the smell off putting and it is one of the reasons I tend not to drink darkly roasted coffee. It's possible that the particular roast and beans the manufacturer is using just has an unusual smell profile.
Freeze drying coffee (theoretically) removes all the moisture from it. Even roasted coffee has some moisture left in it, so the scent profile of freeze dried vs regular coffee should be different.
It's also possible the packager is putting some gas into the containers at the time of sealing. If you have gone to all the trouble of freeze drying, it's important to not put moisture back in the product, and even regular humidity in a room can do that. Do you notice the smell just when the package is opened? Or does it persist after you have had the can opened for a day or so?
