Question: What is manna? Is it spiritual food? A metaphor for HaShem (G-d), the provider? Is it physical sustenance? If so, were its characteristics the same for every man, woman, child, animal? In texture? Taste? Quantity?
Answer: Before we get to the more famous sources, it’s important to recognize that clear verses in the Torah address your question. See Numbers 11:7-8 that the manna was like “gad (coriander) seed” and tasted like “dough kneaded in oil”. As for its texture, it could be “ground”, “pounded” or “cooked”, if that tells you anything. It also gave the appearance of a “b’dolach”, a brilliant gem.
The only problem is, when we look back to Exodus 16:31, there manna’s taste is described as “dough fried in honey”. Earlier, the verse also describes it as “lechem/bread”, which has a different taste still. The Talmud (Yoma 75b) recognizes this triple teaser and explains that the manna tasted differently depending on the age and needs of its eater. Rebbe Yossi bar Rebbe Channina explains that it tasted like bread to young adults, dough kneaded in oil for the elderly, and dough fried in honey for children.
Earlier (Yoma 75a), the Talmud mentions the idea of the manna having many tastes, comparing it to mothers’ milk which also has many tastes. Rashi explains this as referring to how a mother’s milk may taste like the food she just ate (besides its usual milky taste). From here I would presume that the manna had a regular taste, as described by the verses in the Torah, but a person could also detect other tastes in it, depending on their interests and appreciation.
I assume this may be similar to wine connoisseurs who focus on appreciating many different subtleties in a simple glass of fermented grape juice. If we focus on appreciating the kindness of Hashem, there is no end to the wonder we may encounter. (To quote a Yiddish adage: if we’d only focus on thanking G-d for the good, we wouldn’t have time to complain about the bad / Ven me zol Got danken far guts, volt nit zein kain tseit tsu baklogen zich oif shlechts.)
As far as sources to look into this more, the main discussion of manna in the Talmud is found in Yoma 75a-b, though it begins discussing manna a little before that and continues a little later. A debate between Rabbi Akiva and Rabbi Yismael is recorded there over whether manna is identical to the sustenance of angels or just an extraordinary human food. This may relate to your question of whether it was physical or not.
The bottom line is that the manna certainly was a miraculous food, thus it is difficult to come up with an absolutely clear picture of it for ourselves, since miracles are difficult for us to comprehend. On the other hand, we are meant to learn from the manna to appreciate the hidden miracles inherent in the ‘ordinary food’ that we eat today—what a Divine gift it is that the sun shines constantly in the sky, a seed grows up from the ground, a calf from a single cell—and us from all of that.
All the Best,
Maimonides Society at Yale, CT