Batch formula scaling, filling and cost

It turns a formula in percent (or the amounts from a pilot batch) into a weighing list for the batch size you need: by number of containers, by weight or by volume. It allows for reactor and filling losses, rounds each weight to your scale’s resolution and works out batch volume, active content and cost per pound, per gallon and per container. In the example, 500 one-gallon jugs of dish detergent take 4,327.53 lb on the scale.

Write qs in the amount of the ingredient that balances the formula, usually water. In the example the other eight ingredients add up to 19.51% and water takes the remaining 80.49%. Without a q.s. line, if the sum is not 100% (say 98.5%), each amount is divided by the sum and a notice says "Sum = 98.50%: the formula was normalized to 100%". Always read that notice: it often flags a typo.

First comes the mass that must reach the containers: 500 × 1 gal × 8.526 lb/gal = 4,262.8 lb. That is divided by what survives the losses, (1 − 1%) × (1 − 0.5%), giving 4,327.5 lb. Each ingredient is then rounded to the scale resolution (0.01 lb in the example) and the q.s. ingredient closes the total, about 507.6 gal in the tank.

Each raw material’s specific gravity is on the supplier’s certificate of analysis or technical data sheet; for solids that dissolve it only affects the calculated volume. Without a measurement, the calculator estimates product density from the ideal blend, 8.526 lb/gal (SG 1.022) in the example. If you measured the finished product with a hydrometer or pycnometer, enter it: it then governs batch volume and container count, since many blends shrink or expand by a few percent.

Raw materials for the batch cost $707, or $0.166 per pound filled with losses included. Each jug holds 8.53 lb of product ($1.41) plus $1.15 for bottle, cap, label and case share, for $2.56 in total. The Pareto chart shows three ingredients (sulfonic acid, sodium laureth sulfate and fragrance) make up 83% of the cost, so that is where price negotiation pays off. Labor, energy and overhead are not included: add them before setting a selling price.

It shows and prints only what the operator needs: phase, ingredient, %, weight, volume, a blank column for each raw material lot, a check box and "Weighed by", "Checked by", "Date" and "Product lot" lines. Prices, costs, the Pareto chart and the priced ingredient list are hidden on screen and in the PDF, which protects the commercial formula. To change the formula, switch back to Cost report, edit, and switch again.

It does not account for reactions (such as caustic neutralizing the sulfonic acid), evaporation or ingredient-specific losses, and active content is a simple sum of % × each raw material’s content. Weighings below 20 scale divisions carry more than 2.5% rounding error and trigger a warning; in the example the dye (0.43 lb) is 43 divisions. It also does not check FDA or EPA requirements for cosmetics, cleaning products or disinfectants: registration, labeling and ingredient limits stay with your regulatory lead.