What happens to the refuse once the oil is distracted?
When the oil production is done the refuse leftover has many uses. For the Livingston's (who are also in the cattle industry) much of the refuse is spread back onto the fields. They also use it as bedding for their cattle. One day Gene accidentally discovered another use for it: Mint Compost (which happens to be great for gardens and wonderful crops!). Sometimes when the pastures for their cows were getting short, they would take some of the mint refuse and dump it in the fields for the cattle to eat. The following year, they planted corn in that same field. One day Gene happened to be driving by the field and wondered to himself; "why in the world is the corn so tall in that spot?" It was way above the other corn in the rest of the field. He pondered that for several days before realizing, "that's where I dumped that mint cheese!"
Quick fact: Mint cheese refers to the mint refuse when it's finished. The first stills contained big round vats (6 or 7 feet across and 7 feet deep) When it came out of these vats, it was in this round cake form, like you see with old cheese factories. So, everybody started calling it mint cheese.
Current Mint Production
Mint is still grown in the Midwest, but it has really taken off in the Pacific Northwest (it has a good climate with heat, mint loves heat if it has water). It's really become smaller across all of the US in general with the production of synthetic and artificial products. Worldwide, other countries have started to grow it as well. So, while there is still a market for it, it's not what it once used to be.
Dairy, corn and soybeans have also become more stable commodities, which make it harder for the next generation to want to keep it going. It's a labor-intensive crop as well. With instability in the mint market, sometimes it's harder to sell, you may have to sit on it for years.
The Livingstons sell a fair amount retail, but also sell large amounts to wholesalers who in turn sell it to larger companies for numerous products. Currently their farm includes 30 acres of mint; two acres of peppermint and roughly 28 acres of spearmint. They used 300 acres back in the heyday.
Mint is a perennial, so you don't have to plant it every year. It's planted from a stolon, which looks like a cut up piece of root. The planting machine for farms looks like a backwards manure spreader. It goes up through a beader and is then put in rows.
"You should rotate peppermint around every 3rd year and spearmint every fifth year. It's best to rotate, but if everything goes right you can keep a field going." The Livingston's once had a field that was twenty years old, their best field for mint! One year, there was just nothing there, "we had pushed it too far."
"You want it to be hot when you're harvesting, that brings the oil out of the plant. The hotter it is, the more oil you get."
Typically, native spearmint should be harvested the last week in June or the first week in July. Peppermint comes along a little later, by a week or so. The harvest will carry over, because you can't harvest it all at once. It even goes over into August sometimes. If you harvest early enough, it's possible to get a second harvest in the same year.
Quick fact: Mint sends off a scent no matter what time of year it is, but the closer you get to harvest, the more intense it is.