Liquor Ratio, OWF, and What a Batch Really Costs
Dyehouse costs hide in ratios. The recipe says two percent on weight of fabric; the vessel says 1:8 liquor ratio; the invoice says the chemical bill grew again. Between those statements sits arithmetic that every dyeing manager knows and surprisingly few factories systematize, which is how the same batch can be costed three ways by three people.
The two ratios that rule the vessel
Liquor ratio is water to goods: at 1:8, a 400 kg batch runs in 3,200 liters. It drives everything scaled to bath volume: salt in grams per liter, auxiliaries dosed on the bath, plus the steam to heat that water and the effluent to treat it afterward. The liquor ratio calculator makes the bath math instant, and the strategic point durable: machines that run lower ratios save chemicals, steam, water, and effluent on every single batch, which is why liquor ratio belongs on the machine-selection scorecard, not just the recipe sheet.
On weight of fabric governs the dyes and fiber-reactive chemistry: two percent OWF on 400 kg is 8 kg of dyestuff regardless of bath size. The recipe OWF calculator turns recipe percentages into weighed quantities per batch, which is exactly the arithmetic that goes wrong at 2 a.m. when a batch is scaled by hand from 400 to 350 kg and one line of the recipe is not.
Batch cost, assembled honestly
A batch's chemical cost is the sum of both families: OWF items priced per kilogram of fabric, bath items priced per liter at the actual ratio, the batch chemical cost tool stacks them. Add the utilities that scale with the bath and the picture completes: the same shade on the same fabric costs measurably different money at 1:6 versus 1:10, and a re-dye, as the RFT piece priced out, pays the whole stack twice.
Recipes are lots too
The systemic point: a recipe executed is consumption, and consumption should post against chemical lots the same way fabric issues post against fabric lots, the lot discipline applied to drums and sacks. That closes three loops at once: chemical stock that reconciles, batch costs that come from records rather than estimates, and the input side of the story a Digital Product Passport will one day ask you to tell.