Raw materials create two opposite risks for a maker. Too little stock can stop a batch and delay orders. Too much consumes cash, fills shelves, and may expire or become unusable before it reaches production. The right answer is not “buy more” or “keep inventory lean.” It is to set purchasing rules from actual demand, lead time, risk, and usable stock.
Whether you use cards, a spreadsheet, or raw material inventory management software, the discipline is the same: know what is physically available, what is already committed, when replenishment can realistically arrive, and which materials need tighter control.
Build a trustworthy material record
Start with one record for each ingredient, component, and packaging item. Duplicate names such as “amber bottle,” “8 oz amber bottle,” and a supplier SKU can make the same item look like three different stocks.
A useful record includes:
- a unique internal item name or code;
- description, specification, and approved supplier item number;
- purchasing, stocking, and production units;
- verified unit conversions;
- storage location and conditions;
- supplier, normal lead time, and minimum order quantity;
- lot or batch identification when relevant;
- received, expiry, or retest dates when applicable;
- quality status: quarantined, released, rejected, or expired.
Treat units carefully. A case, bottle, kilogram, and gram are not interchangeable labels. If oil is purchased in 20-kilogram pails and issued in grams, document that conversion rather than recalculating it for each formula.
Specifications matter too. Two jars with the same capacity may have different neck finishes. A replacement pigment can change color, and a fragrance substitution can affect performance or labeling. Record approved alternatives instead of letting substitutions happen silently during a shortage.
Separate on-hand from available
A shelf count alone does not tell you what production can use. Some stock may be reserved for released orders, awaiting inspection, expired, damaged, or below the practical amount needed for another batch.
Use a basic availability calculation:
Available quantity = released on-hand quantity + confirmed incoming quantity − committed quantity
Keep confirmed incoming stock visible but distinct from stock already received. A supplier promise is not a physical receipt, and delivery dates can move.
When materials arrive, count or weigh them, compare the shipment with the purchase order, inspect relevant condition or documentation, assign the storage location, and record the received lot. Do not make questionable stock appear usable merely to keep the schedule moving. Put it on hold until someone with defined authority decides its status.
Set reorder points from consumption and lead time
A reorder point should reflect what the workshop is likely to consume before the next delivery can arrive.
A simple starting formula is:
Reorder point = expected demand during lead time + safety stock
Suppose a studio uses 12 kilograms of wax per week and replenishment normally takes three weeks. Expected lead-time demand is 36 kilograms. If the business carries 12 kilograms of safety stock, the reorder point is 48 kilograms.
Use the same time unit for demand and lead time. Then adjust the estimate with real information: seasonal demand, minimum order quantities, scheduled promotions, supplier shutdowns, ocean freight, and open wholesale commitments.
Choose safety stock intentionally
Safety stock protects against variation, not poor recordkeeping. Keep more coverage when an item is critical, has volatile usage, comes from a single source, or has unreliable lead time. Keep less when it is inexpensive to obtain quickly, easily substituted, stable, and used predictably.
Do not apply the same “four weeks of stock” rule to every item. A custom printed carton and a locally available cleaning cloth do not create the same operational risk.
Measure actual supplier lead time
Track the date ordered, date promised, and date received. Average lead time alone can hide unreliable deliveries. A supplier averaging 14 days but ranging from 7 to 30 days requires different planning from one consistently arriving in 15 days.
Review short shipments, defects, documentation problems, and response time alongside price. The lowest unit price can become expensive when late or unusable material interrupts production.
Prioritize materials by money and risk
Not every stock item deserves the same counting frequency or management attention. Group materials using value, operational criticality, shelf life, and supply risk.
An expensive active ingredient may warrant frequent counts and restricted access. A low-cost cap may also deserve close attention if no product can ship without it. Conversely, abundant standard cartons may need only a simpler routine.
For each high-risk item, identify at least one response:
- qualify an alternate supplier or specification;
- place orders earlier during known peak periods;
- negotiate smaller, more frequent deliveries;
- hold additional safety stock with a defined maximum;
- redesign packaging around a more available standard;
- document an approved substitution and its labeling implications.
Alternates need review before an emergency. A supplier’s sample should be tested against the real product and process, with any quality or regulatory implications addressed.
Protect shelf life and traceability
Store materials under the conditions required by their specification. Use first-in, first-out for stable stock or first-expire, first-out when dates determine usability. Clear location labels reduce the chance that an older lot remains hidden behind a new delivery.
Where safety, quality, claims, or customer requirements make traceability important, record which supplier lot entered each production batch. That connection helps narrow an investigation or withdrawal instead of treating every finished unit as affected.
Packaging deserves similar control. Labels, cartons, and inserts can become obsolete after an address, ingredient statement, claim, or design change. Buying a year of printed packaging may reduce unit price while creating write-off risk.
Count in small, regular cycles
An annual physical count is too late to explain months of drift. Use cycle counts: check a manageable group of items each week, with high-value or high-risk materials counted more often.
When a count differs from the record, investigate before adjusting. Common causes include unrecorded batch use, incorrect unit conversion, waste, returns placed in the wrong location, receiving errors, samples, or two similar items being confused.
Track inventory adjustment reasons. Repeated “unknown” adjustments indicate that the movement process needs attention. The objective is not a perfect-looking system balance; it is an honest record that helps production and purchasing make safe decisions.
Review cash as well as availability
Inventory carrying costs include more than purchase price. Materials occupy space, require handling, can be damaged, and tie up cash that cannot pay labor or other bills. Review slow-moving and aging stock monthly.
For each item, compare quantity on hand with recent consumption and open demand. Then decide whether to pause purchasing, use the material in a planned run, return it, sell it where appropriate, or write it off according to accounting and safety requirements. Never use expired or nonconforming material simply to avoid recognizing a loss.
Kerno can connect material records, purchase receipts, lots, formulas, production use, and current availability. A connected system reduces duplicate entry, but reorder settings still need regular review when demand or supplier performance changes.
Create a weekly materials routine
Once a week, review shortages for the next production period, overdue purchase orders, materials approaching reorder points, held or expiring stock, and unexplained count differences. Assign each exception an owner and next action.
Strong raw-material management is not about maximizing shelf quantity. It is about ensuring the right approved material is available when needed while keeping cash, age, and supply risk visible.
