Sizing runs in one direction. Start from a model number and hope your product fits, and you end up with equipment that holds the batch but throttles the throughput. Start from the water your product has to give up, and the machine is decided for you.
Uses the water load from the panel on the left. Every figure below is yours — we publish the instrument, never our number.
The arithmetic, in full: dry solids = batch × (1 − starting moisture); finished weight = solids ÷ (1 − final moisture); water removed = batch − finished weight.
This is the whole method, published in full. Nothing here is proprietary — it is thermodynamics and arithmetic, and you should be able to check any vendor’s recommendation against it, including ours.
01 — Characterize the product. Starting moisture, target finished moisture, structure, fat and sugar content, and how it loads onto a tray. Fat matters because it loads the condenser differently; structure matters because it decides whether the shelf can serve it at all.
02 — Set the batch weight. How many wet pounds go in per cycle. This is the number that most strongly suggests a size class, and the only one most buyers arrive with.
03 — Calculate the water load. Solids = batch × (1 − starting moisture). Finished weight = solids ÷ (1 − final moisture). Water removed is the difference. A 1,000 lb batch at 80% dried to 2% gives up 795.9 lb of water.
04 — Derive the removal rate. Water removed ÷ target cycle hours. This is the rate the system must sustain continuously, not touch as a peak. 795.9 lb over 24 hours is 33.2 lb/hr, every hour, hour fourteen included.
05 — Match machinery to that rate. Condenser, refrigeration and vacuum sized together against it. Shelf area is an output of this step and never the starting point.
This is the single most common and most expensive mistake in commercial freeze drying, and the spec sheets are structured in a way that encourages it.
Two systems can advertise identical shelf area and behave nothing alike, because shelf area says how much product fits and says nothing about how fast the water leaves. The differences live in condenser ice capacity, refrigeration capacity under sustained load, and vacuum performance at working pressure — and those are the numbers rarely printed side by side.
The practical symptom is always the same: the batch fits, the cycle runs long, and the plant quietly makes fewer batches per week than the business plan assumed. Nobody notices at commissioning. Everybody notices at the end of the first quarter.
You do not need a specification to get a useful answer. You need to describe the product.
Batch weight, starting moisture, target finished moisture, and how the product loads — flat on a tray, piled, whole pieces, liquid in a pan. That is enough to size the run, name a configuration, and tell you honestly whether buying or contracting is the cheaper answer for your volume.
If you do not know your starting moisture, say so. It is measurable, it is worth measuring, and it is the number that moves everything downstream.
Start from the pounds of water one batch must remove, not the machine’s advertised capacity. Take batch weight, subtract the finished dry weight, and you have the water load. Divide by target cycle hours for the removal rate the system must sustain. That rate selects the machine.
Total the cost of one cycle — energy, labor, consumables, allocated overhead — and divide by the pounds of water that cycle removed. Not pounds of finished product: pounds of water. That figure is comparable between machines, between vendors, and between your own products.
Because it would be a performance claim, and it would be wrong for your product. Cost per pound depends on your utility rates, your labor, your loading practice and your product. We publish the formula so you can run it on your own numbers, including on our quotes.
No. A larger chamber holds more product; it does not remove water faster unless condenser, refrigeration and vacuum scaled with it. Capacity and rate are different questions, and only rate decides cycle time.