Cleaning Cotton Takes a Lot of Hot Air at the Gin

 Imagine needing to take a shower 10 times before you become squeaky clean.

Cotton going through a dryer at the gin.

Imagine your heart surgeon needing to scrub her hands 10 times before she’s ready to operate.

Or imagine needing to wash your new car 10 times before it regains its luster.

Well Matt Toste can imagine such a tedious cleaning process with freshly harvested cotton. Believe it or not, cotton needs to be cleaned 10 times before its ready to be pressed into a 500-pound bale and then ready to be shipped to the warehouse.

Here’s something even more impressive: The 10 cleanings take only 45 seconds from start to finish. (That’s like taking those quickie showers during the height of our drought a couple years ago.)

Cotton from a module being broken up before entering gin.

“It’s moving. Every time a piece of cotton hits the machinery we’re cleaning it. We’re cleaning, cleaning and cleaning,” says Matt, manager of the Westside Farmers Co-op Gin in the Firebaugh area of Fresno County.

Certainly Eli Whitney would be impressed. You may recall Whitney invented the cotton gin in the 1790s, the first mechanical process to remove seeds from cotton. The cotton gin is considered one of key inventions that triggered the industrial revolution in the South.

Before the gin, seed removal was quite labor intensive. Whitney’s gin – which is short for engine – could process about 55 pounds of cotton in a day. Imagine that.

Inside the gin operation.

First, let’s step back and explain why and how cotton is ginned.

Cotton fiber, or lint, is produced in seed pods on the cotton plant. Seeds, which are interspersed with the fiber, must be removed from the lint. Other things such as leaves– called trash by the industry – must be removed so that the cotton comes out clean and ready to be pressed into a bale. The cotton bales then go to a spinning mill to produce yarn or cloth.

In the past, we talked about the how cotton is picked by a harvester and the fiber is compressed into large rectangular or round modules, depending on the harvesting rig. A round module contains enough cotton to produce 4 to 7 bales, depending on the brand of harvester. A conventional rectangular module is bigger than the round one and contains enough fiber to produce almost 18 bales. Picking rigs that produces round bales require fewer employees in the harvesting process.

Here’s what happens after the modules arrive from the field. The modules are loaded onto a feeder to break apart the compressed fiber. The cotton then is fed into a heated dryer to take out excess moisture and moves into a series of cleaners.

Cleaned cotton pressed into a 500-pound bale.

“What the heat does is it loosens up the trash in the cotton,” Matt says. Air pumped through the cleaners keep the cotton bouncing around to separate the small leaves and other trash from the lint as well as move the cotton from cleaner to cleaner. 

“Air is very crucial in the gin to make it run very efficiently and get the trash out,” Matt says. After going through a sixth cleaner, the seed is then separated and sent to a conveyor belt, which sends the trash and seed to large mounds outside the gin.

Cotton seed is put into a mound outside the gin.

The seed is sold as feed for dairy cows. At the same time, the fluffy trash of small leavesis piled high outside the gin and is sold for mulch. To produce one 500-pound bale, the gin has to remove about 800 pounds of seed and 200 pounds of trash.

Cotton bales ready to be taken to a warehouse.

During the ginning process, two small bags of lint samples are pulled from the production line. One sample is sent to the U.S. Department of Agriculture and the other heads to a cotton warehouse selected by a grower.The USDA will analyze the samples and classify the lint according to color, length and strength and absence of trash. The other sample is used by the cotton marketer to demonstrate the properties and quality of the fiber to prospective buyers.

For the most part, Matt says, “We have premium cotton going out.”