Small-Batch Production Planning Playbook

Why most small-batch plans drift toward over-production

Three forces pull batch sizes upward: equipment capacity ("the wax melter holds 12 lb, may as well fill it"), supplier MOQs ("the case of 64 jars was cheaper per jar"), and the "while we're set up" argument ("the kitchen is already messy"). All three are about producer convenience, not customer demand. Each one, taken alone, is reasonable. Stacked together every week, they produce a freezer of unsold buttercream cakes, a shelf of candles that lost throw at month seven, and a 200-bar soap run that the soap-of-the-month subscriber base will work through over fourteen months — long after the cure-rack space could have been earning new revenue.

The playbook re-anchors the planner on demand. Demand sets the ceiling; shelf life sets the cap; honest labor cost picks the smallest batch worth running; WIP discipline keeps the next batch from compounding the miss on the last one. The five principles on page 2 turn each of those into one decision the demand-driven planner makes differently than the equipment-driven planner.

How the demand-driven batch-sizing formula works

The formula on page 3 is intentionally arithmetic, not algebra: Target batch = (weekly unit run rate × weeks of cover) + safety stock − on-hand inventory. Weekly run rate is a trailing 4–8 week average pulled from sales records. Weeks of cover is "how long until I run this SKU again" plus a small buffer. Safety stock absorbs a sales spike or a missed cycle. On-hand inventory is the count of finished units (plus any WIP that will finish in time to sell) on hand the day the production run posts.

Then the cap: take the smaller of (units saleable before the earliest-expiring component fails) and (the batch size where per-unit fully-loaded cost stops dropping meaningfully — what the Recipe Scaling and Soap Cost-Per-Bar calculators in this resource library both call the batch-curve elbow). The shelf-life ceiling is non-negotiable. The cost-curve elbow is where the per-unit savings from another doubling shrink to a small fraction of what the previous doubling delivered — the playbook calls this "the elbow" to make it nameable and uses the worked candle example on page 3 to illustrate the diminishing-returns shape with one set of inputs (your numbers will differ, so plot your own curve in the linked Excel calculators).

In the worked candle example on page 3, the math says target 45 units and cap 36 units. Run the cap. The remaining 9 units of demand get covered by the next run in roughly three weeks rather than by oversizing this run and tying up wax, jars, and shelf space for a month and a half.

Why WIP discipline matters more than finished-goods discipline

Cured-but-unwrapped soap, cooled-but-unfrosted cakes, bottled-but-unlabeled hot sauce — work in progress sits between "the run is done" and "units are saleable." It ties up cash and storage without earning anything until it crosses the finish line. Most makers track finished goods carefully and ignore WIP entirely; the playbook treats them as one bucket on the Weekly WIP Tracker on page 5 because, from the customer's perspective, an unwrapped bar of soap is an unsold bar of soap.

The discipline: plan finishing labor for every run before the run starts, and don't pour or bake a second batch until the first is shipped or shelved. The WIP Tracker on page 5 surfaces the SKUs where WIP has piled up — finished on-hand at zero, WIP at twelve, days of cover at eight — so the next decision is "spend Saturday morning wrapping the cured batch," not "schedule another pour day."

How the Post-Run Audit closes the loop

The "I made 200, sold 30" trap is real. It usually has one of six causes: demand was overestimated; the batch oversized vs. shelf life (the cap on page 3 was ignored); pricing crowded out demand; channel mismatch (the SKU sold elsewhere, not here); seasonality miss; or quality drift. The Post-Run Audit on page 6 walks each one as a checkbox so the diagnosis names a specific recovery action — recompute the run rate from a fresh trailing eight weeks, run the pricing review, mark the seasonal calendar — instead of a vague "we made too many."

The single most clarifying number on page 6 is profit per hour worked. Revenue from units sold to date, minus total batch ingredient and packaging cost, divided by every hour spent on the batch (setup, active production, cleanup, finishing, packing). Compare against your target hourly rate. If the number is below your floor, the batch sized you out of the rate the rest of the business is supposed to support — and that is information you can act on for the next run, not just lament about this one.