Nothing Goes In

The peanut process is subtractive, and the proof is the layer of oil in the jar.
There is a simple way to judge how heavily a process intervenes in a food. Ask what gets added.

For peanut, the answer is nothing.

I want to walk through the whole process, because "clean label" is a phrase I distrust in almost every context I hear it used, and this is the one crop where I think it survives contact with the actual production line. Not as a claim. As a description.

Impurities come out. Water comes out. Shell comes out. Damaged kernels come out. Skin comes out. There are no solvents, no chemical extraction, no additives, no preservatives. The only transformations applied are heat and mechanical grinding. What reaches the customer is the same kernel that left the field, with fewer things on it.

Here is the sequence:

From the field

Peanut is a geocarpic crop. The flower is pollinated above ground, then the peg turns downward under positive geotropism and buries itself, and the pod matures underground.

That is unusual even among legumes, and it has a direct consequence for processing that nothing else on a spec sheet will tell you: the harvest arrives carrying soil. Not as a failure of good agricultural practice. Structurally, because the fruit grew in it.

Before the crop reaches the plant it is dug, inverted and windrowed for several days. Sun and wind do a large share of the dehydration. The first industrial step has not happened yet, and the crop has already lost most of its water to weather.

Cleaning and drying

The first thing that happens at the plant is the separation of foreign material: soil, stones, plant residue. Only then is drying completed, bringing moisture down to the range that allows the kernel to be held without deterioration.

Storage in shell

Once clean and dry, peanut is stored inside its own pod.

This is not logistics convenience. The shell is a natural physical barrier that protects the kernel from light, oxygen and mechanical damage. The best available packaging for a peanut is the one the plant grew around it, and the industry knows it well enough to build its storage around the fact.

Shelling and sorting

Shelling releases the kernels, and everything comes out at once: every size grade, and also kernels with damage of natural origin — insects, fungi, processes that belong to the field. No harvest anywhere is free of that. Anyone who tells you otherwise is selling something.

Then comes sizing and, above all, electronic sorting. Optical machines analyse kernel by kernel and eject the defective ones.

This step deserves a precision, because it is where the subtractive logic is clearest. Damage is eliminated by removing the kernel, not by treating it. That is the difference between taking out what does not work and correcting it chemically. It is also the primary defence against mycotoxin contamination, because visible damage correlates with risk.

Blanching

Blanching is the removal of the tegument, the skin, which is roughly 3% of kernel weight. It runs in two stages: controlled thermal treatment in continuous multi-zone ovens, between 70 and 95 °C, followed by mechanical abrasion with abrasive-coated rollers.

The heat does not cook the kernel. It creates differential expansion. The cotyledon expands at close to twice the rate of the skin, and that tension breaks the adhesion between them. Only then can friction separate the two without damaging the kernel.

That thermal step leaves two favourable effects behind. It lowers moisture from 7–8% to 4–5%, and the reduction in water activity improves microbiological stability. And it deactivates the kernel's own enzymes — lipoxygenase, peroxidase, catalase — which would otherwise accelerate oxidative rancidity and browning.

Now, a point that usually goes unnoticed, and one I want to state carefully rather than conveniently.

There are four ways to blanch a peanut: with hot water, with alkali (immersing the kernel in sodium hydroxide solution), with hydrogen peroxide, and dry. The three wet methods all require a subsequent drying operation, and all three have been reported to affect taste and appearance. Dry blanching — heat and friction, nothing else — is for those reasons the dominant method across nut processing generally.

I am not going to present that as a distinction. It would be easy to, and it would be misleading. Dry blanching is the industry norm, and a US processor's domestic suppliers are almost certainly using it too.

What is worth knowing is that the alternatives exist and are permitted. Caustic soda and hydrogen peroxide are real blanching routes, in commercial use somewhere in the world, on some products. So the useful question for a buyer is not whether their supplier blanches dry. It is whether they know — for every link in the chain, including the ones they did not contract directly. In my experience that question is asked far less often than it should be.

One more thing about blanched peanut that surprises people: despite the thermal treatment, it is still raw. Not roasted, not salted, not fried. Bare kernel, ready for the manufacturer to process however they need.

Roasting

Roasting is where flavour appears. Maillard reactions between sugars and amino acids generate the aromatic profile of roasted peanut, which simply does not exist in the raw kernel.

It is also a microbial reduction step — and here a precision is owed, because this is the one place in the whole process where imprecision has killed people.

Roasting functions as a lethal step when the time-temperature combination is validated and verified. Not by virtue of heat having been applied. The distinction is not semantic. It is exactly the gap that explains the most serious contamination episodes in this industry's history.

A supplier who understands their product does not say that roasting sterilises. They say how they validate their process. If you are evaluating an origin and you hear the first sentence rather than the second, that tells you something.

Peanut paste

And here the process becomes almost trivial. Peanut paste is roasted peanut, ground. That is the entire formulation.

Grinding ruptures the cell walls of the cotyledon and releases the oil held in the oleosomes, the kernel's lipid bodies. That released oil is not emulsified with anything, so it separates by density. It rises. Solids concentrate at the bottom.

Worth noting that peanut paste and peanut butter are not the same thing, and in the United States that is not a matter of preference but of a standard of identity. That deserves its own piece, and it will get one.

What all of this amounts to

Impurities, water, shell, damaged kernels, skin. That is everything that leaves. Nothing enters.

The complete process consists of removing what does not belong and applying heat to develop flavour and assure safety.

I spend a lot of my working life on regulatory documentation, and most of it exists because food systems are complicated: things are added, transformed, recombined, and the paperwork has to track all of it. Peanut is the rare case where the honest description of the process is shorter than the marketing version would be.

For a manufacturer looking for clean-label ingredients, that is not a positioning statement. It is a literal description of the line.