Admixture is material mixed in with the spice that is not the spice itself, most often other seeds, weed seeds, broken seeds and bits of plant such as stalks and husk. In the Indian seed spice trade it is usually counted separately from stones, dust and other non-plant foreign matter.
How much is acceptable depends on the grade and on what you do with the product. The key is to define the term and the limit in your contract, because suppliers and buyers use it differently.
Admixture, foreign matter and extraneous matter
These three terms overlap, and different specs draw the lines in different places. A common way to separate them is below, but write your own definitions.
- Admixture: other seeds and plant parts, including weed seeds, other crops and broken or shrivelled seeds of the same spice if your spec counts them.
- Foreign matter: material not from the plant, such as stones, soil, glass, metal, plastic, string and insect fragments.
- Extraneous matter: often used as an umbrella for everything that is not sound product of the named spice.
- Purity: the share by weight of sound product. A 99 percent purity grade allows up to 1 percent of everything else combined.
What drives admixture
- Weeds harvested with the crop, especially where fields are not cleaned well.
- Mixing of lots and crops at the APMC market and in traders' stores.
- The cleaning line: sieves and aspirators take out much, but seeds of similar size and weight can remain.
- Deliberate mixing: adding cheaper seeds or exhausted spice to add weight is a known form of adulteration. See avoiding spice adulteration.
How much is acceptable
There is no single standard figure. As a guide, higher grades and sortex-cleaned lots carry less admixture than machine-cleaned or market-grade lots, and products sold whole to consumers need tighter limits than products that will be ground.
- Retail whole spice: set tight limits, and consider a sortex grade.
- Grinding or blending: a machine-cleaned grade may be enough, if your purity figure is met.
- Extraction: admixture matters mainly for yield and contaminants.
- Any use: set a zero tolerance for toxic weed seeds where your food law requires it, and for stones and glass.
How to test it
Admixture is measured by hand-picking a weighed sample and weighing each fraction. It is simple but slow, so agree the sample size and who does it. A larger sample drawn from many bags gives a fairer result. For grade choice, see machine-clean versus sortex-clean cumin.
How we help
We write clear definitions of admixture and foreign matter into your spec, and our inspectors hand-sort lot samples at the factory before loading so you see the real figure. To set limits that fit your use, request a free sourcing review.