The pomace belt, and what becomes of pomace

Each press family sheds its cake differently. A belt press discharges continuously: the two belts separate at the end of the run and doctor blades scrape the cake off both, dropping it onto a cross conveyor. A pneumatic press opens its drum and tumbles the cake out in one go, so whatever receives it has to take a drum-load at once. A rack and cloth press is stripped by hand, layer by layer, and the cake comes away in slabs that are stacked or barrowed. A basket press cake is dug out.

The receiving arrangement follows from that. Continuous presses feed a belt or an auger that runs the whole shift; batch presses feed a skip, a trailer or a bin that has to be swapped. The commonest design fault in a small plant is a pomace route that is sized for the average rate rather than the peak, so the press waits for the conveyor.

Whatever carries it gets sticky. Pomace is sugar, pulp and juice, and a belt or auger that is not washed down every day ferments, then goes acetic, and then inoculates every cake that passes over it. It is also the reason a pressing floor becomes dangerously slippery within an hour of starting.

Feeding fresh pomace to cattle, sheep and pigs is the oldest disposal route in cider country and it is a real one: the material is palatable, and the residual sugar and fibre make it a reasonable energy feed. What it is not is a balanced one. Pomace is low in protein and in minerals relative to the energy it carries, so it is fed as part of a ration rather than as a ration, and how much of what stock is a question for a veterinary surgeon or a livestock nutritionist. This site does not publish feeding rates.

The constraint that catches people is time. Wet pomace begins fermenting within hours and moulds within days, and mouldy pomace is not a feed — it is a route by which mycotoxins reach animals. Farms that feed at any scale either feed within a very short window or ensile the pomace properly in a sealed clamp or bags, where the acidification that follows preserves it. A heap in the corner of a yard is neither of those things.

There is also a regulatory dimension that has grown considerably. In many jurisdictions supplying a by-product for animal feed makes the supplier a feed business with registration, traceability and hygiene obligations, even where no money changes hands. That is worth establishing locally before the first trailer leaves the yard.

Spreading pomace on the orchard has an intuitive appeal — the material came from the trees, so it should go back to them — and it does return real organic matter and a useful quantity of potassium. The nitrogen story is the one usually told wrongly. Pomace is a high-carbon, low-nitrogen material, and fresh high-carbon material worked into soil is decomposed by microorganisms that draw nitrogen out of the soil to do it. In the short term a heavy dressing of fresh pomace can immobilise soil nitrogen rather than supply it, and the nitrogen only becomes available later as the microbial biomass turns over.

That is an argument for composting rather than against spreading. Pomace composted, alone or with a nitrogen-richer material, returns a stable organic amendment with its nutrients in a usable form and without the immobilisation. Where fresh pomace is spread it is spread thin and early, not piled.

Three further consequences are worth naming. Pips germinate, so a spread of fresh pomace becomes a carpet of seedlings the following spring. A heap draws deer, badgers, rats and wasps, and a fermenting heap draws them in numbers. And in most jurisdictions spreading a processing by-product to land is regulated as a waste or by-product activity with its own permissions and record-keeping, however agricultural it feels.

Dried pomace is a genuine commodity — it is a standard feedstock for commercial pectin, and apple fibre appears as a food ingredient — but drying a material that is largely water costs a great deal of energy, so this route belongs to plants of a size where a continuous stream justifies the plant. For everyone else the realistic choice is between livestock, land and a digester, decided mostly by what is within a short drive.