Mint in Michigan

By Leroy Barnett

In 1835 Calvin Sawyer, newly arrived in St. Joseph County from Ohio, introduced peppermint to Michigan soil. Though Sawyer disposed of his farm the following year, his effort marked the beginning of the Michigan industry that dominated world mint production by the turn of the century.

Peppermint (Mentha piperita, named for its pepper-like taste) and spearmint (Mentha spicata, named for its arrow-shaped flower spires) are related plants (Labiatae) that are rich in volatile oils called terpenes. These ethereal, complex organic compounds--mainly menthol and carvone--give mint the taste and aroma that make it a favorite for chewing gum, toothpaste, candy and medicine.

The two plants are believed to have originated in the Mediterranean basin, where their earliest uses were for fragrance and flavoring, especially in medicinal products. The first known commercial production of the crop began in England during the mid-eighteenth century. Peppermint and spearmint are not native to North America, but once imported by colonists, they quickly adapted and dispersed. They grew wild or as garden herbs until the 1790s, when the first commercial mint farming began near Cheshire, Massachusetts. Better soils drew the mint industry to the Finger Lakes region of northwestern New York in the early nineteenth century.

Though Calvin Sawyer's mint career was ephemeral, others in St. Joseph County continued to plant peppermint in the county's burr oak openings. By the end of the Civil War, mint production in St. Joseph had increased so much that Michigan rivaled national leader New York as the primary source of supply. Following the Civil War, mint cultivation spread from St. Joseph, first west into Cass and Berrien, then north into Van Buren, Allegan and Kalamazoo Counties. By the turn of the century, 90 percent of the world's supply of mint oil came from an area within a ninety-mile radius of Kalamazoo.

Despite the productivity of Michigan's mint fields, Michigan mint growers at first had difficulty selling their harvests because of unscrupulous farmers who adulterated the oil with turpentine, alcohol or fireweed. Even if those who raised the crop were honest, dealers might dilute the oil to increase their profits. Since there were no established tests for determining the purity of mint distillates, it was difficult to guard against these practices.

The man most responsible for overcoming this problem was Albert M. Todd. Born in Nottawa, St. Joseph County, on 3 June 1850, Todd graduated from Sturgis High School and studied chemistry at Northwestern University. He returned to Nottawa in 1868 to join his older brother in growing peppermint.

Todd Company bottle label—note the award medallions

Todd's first contribution to improving the status and reputation of Michigan's mint was to develop twelve different scientific methods of testing mint distillates for such qualities as odor, taste, solubility, specific gravity and contamination. The first recognized means of grading the oils, these tests allowed adulterated fluids to be detected and avoided. To help drive debased products off the market, Todd explained his findings in speeches and in professional journals.

Once his laboratory techniques were well established, Todd began bottling, sealing, promoting and selling mint oil. In 1875 he marketed the "Crystal White" brand, with his own name serving as a mark of eminence. Todd achieved a reputation for high quality, and his sales eventually exceeded the capacity of his Nottawa works. In 1891 he moved his operations to larger facilities in Kalamazoo.

From his new headquarters, Todd improved Michigan mint husbandry by establishing two commercial experimental farms—Mentha in northeastern Van Buren County and Campania in central Allegan County. The latter encompassed two thousand acres and employed one hundred men. On these plantations Todd promoted research to develop hybrid mint plants and better related agricultural techniques. He and his staff made significant advances in distillation technology and introduced better rootstock to the business. The latter achievement was based on Black Mitcham mint, a hardy variety that Todd imported from England because it produced a higher quality and quantity of mint than domestic plants. By the turn of the century Todd was the largest producer of peppermint oil in the world and owner of the world's most extensive mint acreage.

While many aspects of general farming had been affected by mechanization by the time of Albert M. Todd's death in 1931, mint farming had undergone relatively few changes in its first century.

Since the commercial mint plant is a sterile, complex perennial that seldom produces seed, planting a new mint field required a source of rootstock. For this purpose an old field with healthy growth was plowed to expose the individual roots. These roots were hooked from the upturned soil by hand or pitchfork. To keep these runners from drying out workers piled them into small heaps and covered them until needed.

At one time Mentha Plantation, above, produced about 50 percent of the mint oil in the United States. During World War II the importance of mint oil placed mint on the list of essential crops and led the War Manpower Commission to recommend that growers be given draft deferments.

Before transplanting could occur, the new area had to be readied. This process consisted of plowing and disking the field, then marking it with furrows three feet apart and about three inches deep. Next, the mint stolons or runners--about a quarter inch in diameter and one to three feet long--were placed in a carrying sack, manually separated and strung along each trench, end to end. The person doing the hand planting then covered the channels with soil, and the ground was lightly dragged to ensure a good start.

If the planting was properly done and the weather cooperated, sprouts appeared about every three inches along each furrow two weeks after planting. From this stage the roots grew up and out, spreading laterally until by late summer they had formed a solid green mat. Because yields from mint fields usually declined each year, lands were customarily plowed up every three to five years and either restored with new roots or given over to other crops. Resting the soil from monoculture helped improve fertility and reduce disease, so mint farmers usually chose the latter option.

Weeds in mint produce an inferior oil. Weeding, done by hand, began shortly after planting. Even after farming became mechanized, weeding remained largely a manual task because the delicate mint plants were easily injured by tractors and their implements. In an attempt to lower production costs and labor demands, farmers experimented with grazing animals to weed the fields. Since livestock do not eat spicy mint leaves, cows, goats and sheep were used to consume the unwanted vegetation. Though these beasts removed the weeds, their hooves damaged the crop. Geese, on the other hand, performed the weeding with no adverse effects.

The annual harvesting of mint usually began in late July or early August, when the plants were about two feet high and at 10 percent of full bloom. The crop was mowed by hand, much like clover, and then placed into windrows to dry. After curing to the wilt stage, the hay was loaded on wagons or placed in special containers and taken to the still.

Initially mint oil was distilled by using a copper kettle and a condenser pipe, much like the traditional moonshine stills of Appalachia. (During Prohibition, mint distillery owners were required to have state and federal permits in order to operate.) This slow method of extraction yielded only twelve to fifteen pounds of oil per day.

The introduction of the steam distillery in 1846 increased production to over one hundred pounds of oil daily. In this process the copper kettle was replaced by large wooden vats about six feet in diameter and from six to eight feet deep. Each tub was connected to a boiler from which it could draw steam. After one to two tons of mint hay had been loaded into the vat, the cover was tightly secured and a condenser coupled to the lid. Once the distilling apparatus had been charged with hay and readied, steam was forced into the bottom of the wooden chamber. The mint oil, primarily contained in glands on the lower surfaces of the leaves, was freed by the heat and carried upward with the steam to the top of the vat. There, the hot vapors entered a cooled condenser, which converted the steam to a mixture of mint oil and water. This fluid flowed into a separator, where the oil, which collected on top, was skimmed off. Each load took about forty-five minutes to process and yielded about twelve pounds of oil. It took an acre of mint to produce thirty pounds of oil.

The mint oil created by this procedure was drained into twenty-pound cans, which could be stored for several years without damaging the oil's quality. The relatively tasteless vegetative matter that remained in the vat was removed, dried and fed to livestock. When the mint season was over, a few factories turned to distilling such things as wormwood, tansy, erigeron, wintergreen, sassafras or pennyroyal. Most operations, however, were privately-owned, one-use stills that were shut down in the autumn and not refired until the next year's mint cutting.

 A. M. Todd created the enterprise that included these wagons of peppermint at the Mentha stills. The steaming load consists of mint leaves that have been processed.

Initially, mint oil was used mainly for medicinal purposes, but the popularity of both chewing gum and toothpaste in the early twentieth century provided a new market. In 1984 70 percent of U.S. produced mint oil was consumed in the United States--40 percent of that went to improve the taste of gum and 30 percent to sweeten toothpaste and mouthwash.

During the nineteenth century Michigan mint was primarily grown on natural prairies and in burr oak openings. While these soils generally supported a decent crop, they were often excessively windblown and incapable of shielding sensitive plants from winterkill. To escape these problems, mint farmers in the late 1880s shifted their operations to mucklands, which until then had been generally unused for agriculture. Mucklands offered better protection and rich earth, which significantly increased the yield of mint fields. Furthermore, muck soils had a large water-holding capacity, an important feature for a crop with high moisture requirements. By raising or lowering gates in drainage canals, mint farmers could keep the water table near the surface during the growing season and then drop it when harvesting demanded dry fields.

The low-lying mucklands brought new problems. Poor drainage could retard cultivation and harvesting, flood the crop in wet times or require extensive ditching projects. Also, the growing season in the mucklands was restricted because they were susceptible to frost late in the spring and early in the fall. Nevertheless, the superior yields of muck soils far outweighed their disadvantages, and by the mid-1880s the switch from high to low ground was complete.

Michigan mint received its most serious challenge in the form of verticillium wilt, a fungus that first appeared in mint fields near Mentha in the 1920s. Verticillium wilt is a soil-dwelling disease that invades vegetation through its root system, disrupting the water-conducting elements of the stem. This results in a loss of vitality and often the death of the plant. Even when crops immune to the wilt are grown on contaminated lands in an attempt to eradicate the problem, the fungus can remain dormant in the soil for ten years, waiting to reinfect the next mint planting.

Michigan peppermint plants were severely affected by the wilt. Before World War I, mint production had begun to shift from the southwest to the mucklands of the central portion of the Lower Peninsula. The wilt's devastation of the southwestern fields accelerated the move to the new mint fields, which were located predominately in Clinton County. The mid-Michigan area accounted for nearly a third of the nation's entire mint supply by the 1930s and kept Michigan the world's main source of peppermint in 1940. But the wilt appeared in Clinton County, too, sharply reducing mint yields in the late 1940s.

One of the unique features of mint growing
was the use of geese to remove weeds from mint fields.

During the post World War II period, the Michigan mint industry changed drastically. By the early 1970s verticillium wilt had virtually ended the commercial growth of peppermint in the state. Today most of the nation's peppermint is grown in the Pacific Northwest. Since some spearmint is resistant to verticillium wilt, it is still grown in Michigan. In 1982 Michigan produced 10 percent of U.S. spearmint, ranking it fifth among spearmint-growing states.

In an effort to reestablish peppermint in Michigan, geneticists attempted to create a wilt-resistant hybrid. When this approach failed, Dr. Merritt Murray, an A. M. Todd Company scientist, exposed 100,000 pieces of stolon to ionizing radiation to induce mutations that would tolerate verticillium. Murray's efforts produced two varieties of peppermint that can withstand the wilt fungus and still produce quality oil. These new plants offer hope that the Michigan mint industry can rebound.

Scientific knowledge has also led to many improvements in the processing of mint. Distilleries have been consolidated and automated so that they hardly resemble the operations of a decade ago. Now the hay is sliced into quarter-inch pieces before being treated, an operation that reduces the amount of steam needed to extract the oil. This chopped mint is no longer dumped into a vat and then forked out after cooking. Instead, the cuttings are loaded into large, portable, metal receptacles that can be mechanically moved in and out of distillation tubs. In the more modern facilities, the hay is picked up by a field chopper and blown into wagon-mounted tanks that are designed to serve as individual steam chambers, eliminating even more handling. When full, these containers are towed to the distillery and hooked directly to the steam lines and condenser. In about one hour the distillation process is complete. The spent charge is hauled away and dumped (much like a load of sand) through a large door in the rear of the hopper.

The decline of mint fields in Michigan did not prevent the A. M. Todd Company from remaining a wholesale distributor of essential oils and the nation's largest buyer of mint distillate. Although the company no longer harvests its own mint at Mentha or Campania [two large commercial firms], it still maintains its offices in Kalamazoo and is managed by Todd's sons and grandsons.

Today's A.M. Todd Company: http://www.folexco.com/.