The origin of the word spice comes from the Latin species literally meaning species. In the spoken versions of Latin from the 3rd and 6th centuries it derived to define a substance, a commodity, a spice. We can note that the original word “species” is indeed a feminine noun.
We note, and we define it as such, the first written appearance of the word spice in the Song of Charlemagne's Pilgrimage to Jerusalem. (mid-12th century)
Stanza XII, line 211:
Four but fud li reis in Jersalem the city;
II et li duze per, dear cumpanie,
They remain a great barn, because the emperor is rich.
A muster of Saint Mary begins:
Li hums the earth and claims it in Latin,
Because the language I come from trestute the city;
They sell their wings, their heads and their siries,
Coste, cinnamon, pepper, other spices
And many good herbs that I didn't know how to tell.
Deus is uncore and he who can do justice!
Charlemagne evokes the merchants who sell ginger (Coste), Cinnamon (Canele), Peppers (Peivre) and other good spices (altres bones espices)
In the Middle Ages the word spice came to encompass all kinds of preparations, often sweets (jams, sugared almonds) in which spices were sometimes found. We even had a responsible person in charge of these sweets who was called the king's grocer. In the Roman de la Rose, a medieval poetic work, we find traces of it: “And many a delitable spice That a good mangier makes after the table”
Note again that the word spice is also feminine at this time. In the various Renaissance texts the word spice, which has the same contemporary definition, is also used in the feminine form.
Despite attempts at in-depth research, we could perhaps have found in the past a plausible explanation for the use of the masculine instead of the feminine to determine the spice. But no, no trace.
Although today we sometimes note the use of the word spice in the masculine, spice is indeed a feminine noun: A spice!