Threshing is the process of loosening the edible wheat kernel from the inedible components of the plant, such as the stalk and husk. This separation is necessary for preparing the grain for storage, milling, and consumption. While modern agriculture relies on large machinery, manual threshing remains a practical method for small-scale garden harvests, those with a historical interest, or when mechanical equipment is not available. The following guidance outlines the traditional, hands-on techniques required to process harvested wheat into clean, usable grain.
Readying the Harvested Wheat
The success of manual threshing depends on the condition of the harvested wheat heads. The optimal time for cutting is when the heads are golden and the kernels are in the “hard dough” stage. This means they are difficult to break in half when tested with a thumbnail but are not yet so dry that they shatter easily. Harvesting at this stage helps prevent premature shattering and grain loss.
After cutting, the wheat must be thoroughly dried or cured before threshing. This curing process reduces the moisture content of the grain and straw, making the kernels separate more easily from the chaff during agitation. The cut wheat is typically tied into bundles, known as sheaves, and stacked upright in the field or moved to a dry, covered location for several days to a week. Ensuring the grain is completely dry minimizes the risk of spoilage in storage and improves separation efficiency.
Methods for Separating the Grain
Once the wheat is properly cured, threshing begins by applying force to the heads to knock the kernels free.
For small batches, a simple method involves placing the heads inside a clean, sturdy container, such as a large bucket or trash can, and striking them repeatedly against the inside surface. This action causes the wheat berries to detach and collect at the bottom alongside the broken plant debris.
A more traditional and efficient method for larger quantities is flailing, which uses a simple tool or stick to beat the grain. The sheaves are spread out on a clean, solid surface, historically called a threshing floor, or on a large tarp. The thresher uses a rhythmic, swinging motion to strike the wheat heads with the flail. This loosens the grain from the head and breaks up the surrounding plant material. The thresher must strike the grain with sufficient force to dislodge the kernels without pulverizing the straw, which makes the subsequent cleaning step more difficult.
Another option, particularly for moderate amounts of grain, is trampling or treading. The wheat heads are spread a few inches deep over a clean, durable mat or canvas on the ground. The thresher walks or treads over the spread-out grain, using their weight to crush the heads and push the kernels out of their husks. For very small amounts, rubbing the seed heads vigorously between the hands can also release the kernels, though this is time-consuming for anything beyond a few handfuls.
Cleaning the Grain Through Winnowing
After the kernels are separated from the stalks, the mixture consists of heavy wheat grain and lighter debris, collectively known as chaff. Winnowing is the final step that uses air movement to separate the heavy grain from the light chaff, making the grain clean and ready for use. This technique relies on the difference in density between the kernels and the unwanted plant fragments.
The most practical manual method involves using a steady stream of air, either from a natural breeze or an electric fan. The threshed material is poured slowly and carefully from one container into another, holding the first container high above the second. As the material falls through the air current, the lighter chaff is blown away horizontally, while the heavier wheat kernels fall straight down into the collection container below.
This pouring process must be repeated multiple times, often five or six passes, to remove all the fine chaff and larger pieces of straw. Following air separation, the grain should be examined for any remaining debris. Any remaining debris can be removed by hand or by using screens or sieves to sift out pieces that are too large or too small. The final product is the clean wheat berry, prepared for storage or immediate grinding.