Which basis should be my master—w/w, w/v, v/v, or % solids?

Use w/w as the master unless law or market requires volumetric control. Maintain solids and volumetric renderings as governed views from the same data; execute by mass and compensate volume with density and temperature.

How do we handle density changes with temperature during dosing?

Either dose by mass or apply temperature-compensated density to volumetric setpoints. Lock reference temperature and density tables under Document Control and compute targets in the MES—not on handheld calculators.

When is % solids the right basis?

For concentrates, slurries, and evaporative processes where performance follows dry matter. Author recipes on a solids basis and let the system adjust carrier to hit the target solids with alert/action limits.

Where should rounding and significant-figure rules live?

In the platform. Perform calculations in high precision and round once at presentation. Prevent local overrides; require reasons and e-signatures for exceptions.

Do we need inline sensors to control basis?

Not always. Gravimetric control plus validated lab methods are sufficient for many processes. Inline densitometers and mass-flow with density compensation improve stability when validated and integrated with the MES.

How do we keep labels consistent with execution basis?

Render labels from the same governed basis used in execution. Enforce label verification at print/pack, and block printing if basis or market rules mismatch.

Recipe Scaling & BasisGlossary

Recipe Scaling & Basis – Mass/Density/% Solids

This topic is part of the SG Systems Global regulatory & operations glossary.

Updated October 2025 • Formulation Engineering, Scale‑Up, UOM/Density Governance • R&D, Manufacturing, QA, Packaging, Supply Chain

Recipe scaling is the discipline of converting formulas across batch sizes, sites, and technologies without changing the product. It is not “multiply by ten.” It is a controlled transformation across basis choices—mass‑based (w/w), volume‑based (v/v, w/v), or solids‑basis (% total solids)—with density and moisture making or breaking the result. A formula written in grams at lab temperature is a different animal at plant scale in a jacketed vessel with hot, viscous feeds. The blunt truth: most out‑of‑spec bulks, label errors, and yield variance trace back to sloppy basis logic—ungoverned density tables, casual % solids assumptions, and rounding performed by hope instead of policy.

“If you can’t state your recipe basis in one sentence, you can’t scale it in one shift.”

TL;DR: Freeze the basis (w/w, w/v, v/v, or % solids) under governed Recipe Management; encode density at a declared temperature and compensate at execution; correct for moisture/% solids using validated lab data (e.g., Karl Fischer); do math in mass first, then render other views via controlled UOM conversions; embed rules in a validated MES/eBMR with audit trails. Scale linearly only where physics allows; adjust hold‑ups and heat/mass transfer by study. No spreadsheet bridges. No hand rounding.

1) What “Basis” Covers—and What It Does Not

Covers: how a recipe defines each component target (w/w mass fraction, w/v grams per liter, v/v percent volume, or % total solids) and how those targets convert through density, temperature, and moisture. Basis also covers the rounding, significant figures, and presentation rules for labels and work instructions, and how to re‑express formulas for micro/macro dosing (Micro‑Ingredient Dosing, Macro Dosing) without breaking identity.

Does not cover: waving away density as “close enough,” assuming % solids is fixed for all lots, or linear scale‑up for steps dominated by surface area, shear, or residence time. Basis is math plus physics. Ignore either and you buy scrap or rework disguised as “learning.”

2) Legal, System, and Data Integrity Anchors

Scale‑up choices land in regulated evidence. Recipes are governed under Recipe Versioning & Change Control, executed in a validated MES, and reviewed in the eBMR. Electronic records must meet Part 11/Annex 11 (validated software, unique users via UAM, and tamper‑evident audit trails). All basis tables—densities, % solids, temperature corrections—belong under Document Control and are subject to Laboratory Analyses & Review. If your conversions live in a private spreadsheet, you don’t have compliance—you have luck.

3) The Evidence Pack for Scaling Decisions

To defend scale‑up, show (i) the frozen recipe basis statement; (ii) the density table with reference temperature and method; (iii) the % solids or moisture method (e.g., KF or loss‑on‑drying) with TMV evidence; (iv) rounding/significant‑figure policy; (v) UOM conversions under a governed service (UOM Conversion); (vi) scale‑dependent adjustments (hold‑up, shear, heat transfer) and the studies behind them; (vii) executed examples in eBMR with before/after numbers; (viii) SPC/CPV charts on solids/density (SPC, CPV). Auditors should be able to reconstruct the arithmetic from source records—no interpretive dance required.

4) Basis Options—Say It Once, Use It Everywhere

w/w (mass basis). Every component expressed as a fraction of total mass; total equals 100%. Best for production: scales read mass; mass balances close. w/v. Mass per volume (e.g., g/L). Useful where regulators or specs are volumetric (dose volumes, beverages), but dangerous if density moves with temperature. v/v. Volume fraction; common for solvents or blends sold by volume. Beware non‑additive volumes and compressibility. % solids (w/w). Components expressed as dry solids contributions; water or volatile carrier becomes “qs to % solids.” This basis is essential for concentrates, slurries, and evaporative processes. Pick one basis for the master and generate the other views in software.

5) Density & Temperature—Numbers That Move

Density (ρ) converts mass to volume and back: m = ρ·V. It changes with temperature and composition. Freeze reference conditions (“ρ at 20 °C” or “60 °F”), capture actual temperature at dosing, and either (i) dose by mass only, or (ii) compensate volume with temperature‑corrected ρ. Put density tables under Document Control. If your operator is googling density at the scale, your basis is already bleeding variance into yield. Tie temperature inputs to devices over SCADA and have the MES compute corrected targets, not the operator’s calculator.

6) % Solids, Moisture & Potency—Active vs. Carrier

When suppliers ship aqueous or solvent‑borne materials, your “100 kg” drum may hold 58 kg solids and 42 kg water. If the formula is solids‑basis, you must compute added mass as m_{as‑received} = m_{solids‑required} / (% solids). If your formula is w/w, but product performance depends on solids, you still must monitor solids inputs and adjust carrier elsewhere. Validate % solids measurement (TMV) and lab competence (ISO/IEC 17025). Do not use certificate values blindly; sample lots under GMP sampling plans and trend supplier drift with SQM/SCAR when needed.

7) Rounding & Significant Figures—Where Errors Hide

Do calculations in high precision; round once at presentation and label. Lock rounding policy in the platform (UOM Conversion) and apply consistently. Avoid double rounding when converting w/w → w/v → operator screen. When targets must be split across micro/macro steps, split before rounding, then round each step. If two lines compute different totals for the same batch size, your rounding rules are wrong or undocumented. Fix math centrally; don’t train people to memorize exceptions.

8) Worked Micro Example—Simple, Correct, Defensible

Target: 10.000 kg batch, with 1.0% w/w preservative supplied at 50% w/w in water. Required preservative solids = 0.100 kg. As‑received mass = 0.100 / 0.50 = 0.200 kg. If the formula is w/w, water must reduce elsewhere to keep total mass = 10.000 kg. The MES should compute: add 0.200 kg of preservative solution; reduce process water by 0.100 kg. No head math, no “close enough.” Everything attributable in eBMR.

9) Worked Macro Example—Density & Temperature Compensation

Target: add 1,000 L of solvent at 20 °C, but storage is at 30 °C; ρ(20) = 0.810 kg/L; ρ(30) = 0.800 kg/L. If dosing by volume at 30 °C without temperature compensation, you under‑mass by ~1.25%. Better: dose by mass (target ρ(20)·V = 810 kg) or apply ρ(30) and dose 810/0.800 = 1,012.5 L at 30 °C. Lock the rule in the MES and show the adjusted setpoint on the HMI. If your fix is “tell operators to remember the summer table,” expect variance and arguments at release.

10) Basis and Mixing Order—Process Matters

“qs with water to 100%” is a basis decision and a process step. If viscosity spikes with solids, doing qs before dissolving can trap air and misread the level. Put the qs step where the physics works and document it. For powders that hydrate (gums, proteins), consider Baker’s Percent for hydration control, then convert to w/w for execution. Basis isn’t divorced from sequence—your order can create phantom mass via foam and adhesion if you’re dosing by volume. Dose by mass where possible; measure volume only when you must and compensate for temperature and foam.

11) Concentrates, Dilutions & % Solids Control

When building a concentrate to be diluted downstream, % solids is the hard promise and volume is the soft promise. Express concentrate on a solids basis; adjust carrier to hit target solids ± tolerance with alert/action limits. At dilution, compute required solvent from actual concentrate solids, not the nominal spec. Record actual solids at both ends and reconcile in Mass Balance. Companies that dilute “by eye” to a mark spend the rest of the year explaining yield variance to Finance.

12) Equipment Hold‑Up & Losses—Scaling Isn’t Linear

Bigger vessels don’t scale linearly in dead legs, line volumes, or filter cakes. Quantify hold‑up for each train; encode expected recoveries and losses in the recipe or the execution step. Correct charge amounts so the delivered mass in the mixing zone meets the basis. Link these corrections to mass‑balance closure and yield variance. “We lose ~2% in filters” is lore; measured hold‑up with governed corrections is evidence. Update values under Change Control when hardware changes.

13) Inline Measurement—Close the Loop

Inline densitometers, mass‑flow meters with density compensation, and refractometers (for certain systems) can keep basis honest. Bind instruments to the step via SCADA; stream values into the MES; apply MSA to separate instrument noise from process variation. Inline doesn’t replace lab—use both, reconcile routinely, and lock logic under CSV and retention rules.

14) Lab Cross‑Checks—Trust, Then Verify

Confirm % solids and moisture against validated methods (KF for water; oven solids, GC for volatiles where applicable). Prove method capability in TMV, and lab competence under ISO/IEC 17025. When inline and lab disagree beyond limits, treat it as a data‑integrity signal: stop, investigate, and document under Deviation/CAPA. Never “average” readings to justify shipping.

15) From R&D to Plant—Freeze Rules Early

R&D must author the basis with the formula—not as a footnote. Include reference temperature for density, the solids/potency method, and any scale‑dependent adjustments. Store it in governed Recipe Management; push it through Recipe Versioning to manufacturing. The plant should never “interpret” a new basis on the floor. If the first industrial batch requires a different basis, that’s a change request, not a hallway conversation.

16) Labels, Panels & Claims—Basis Must Match Copy

Label ingredient order (% w/w predominance), net content (mass vs. volume), and any solids‑dependent statements must reflect the executed basis. Drive labels from governed data with Labeling Control and enforce Label Verification on the line. If you claim volume but dose by mass, the density rule must be the same in execution and label copy. Any mismatch is a complaint generator and a regulator magnet.

17) Cleaning, Holds & Time—Basis Drifts With Reality

Solids creep during long holds via evaporation; density shifts with temperature during cleaning transitions. Control hold times under Hold Time Studies; validate cleaning carryover (Cleaning Validation); map temperature during storage and transfer (Temperature Mapping); and monitor environment (EM). Put numbers on the drift, then bake compensations into the recipe or execution plan with approvals—not tribal memory.

18) SPC/CPV on Basis—Make Drift Visible

Track density at dosing temperature, % solids at build and at dilution, and mass‑to‑volume conversion accuracy with SPC and capability (Cp/Cpk). Feed results into CPV. If Cpk is low on solids, improve moisture measurement or tighten supplier controls. SPC is not decoration—it tells you where to spend money (lab, sensors, procedures) instead of hoping the next batch behaves.

19) Common Pitfalls & How to Avoid Them

Dual truth tables. One spreadsheet in R&D, another on the floor. Kill both; centralize conversions in validated systems with audit trails.
Temperature amnesia. Dosing volumes without temperature compensation. Dose by mass or correct volume using governed density tables.
Assumed % solids. Using supplier nominal instead of lot‑tested values. Sample to plan and adjust execution mass.
Rounding drift. Rounding component targets early and often. Round once at presentation.
Scale‑up denial. Copying lab mixing times to 10× volume. Validate time, shear, and hold‑up; document adjustments.
Label math mismatch. Label claims use one basis; execution used another. Drive both from the same master and block prints on mismatch.
Free‑text “qs.” Quantity‑sufficient with no rule is a blank check. Encode qs logic and interlock to prevent overshoot.
Shadow rework. Quiet post‑dilutions to “hit specs.” That’s a change; record it and fix the basis upstream.

20) Metrics That Prove Control

Density conversion accuracy (expected vs. measured mass for volumetric additions).
% solids hit rate at concentrate and at point‑of‑use, with Cpk.
Yield variance vs. plan broken down by basis drivers (density, solids, hold‑up).
Supplier solids drift and time‑to‑SCAR closure.
Rounding exceptions (instances where manual edits were requested—and why).
Label/eBMR parity incidents (should be zero) and time‑to‑correction.
Mass‑balance closure at batch close for basis‑sensitive steps.

Metrics exist to force decisions. If none trigger a change in method, supplier, or device, you’re measuring for comfort, not control.

21) What Belongs in the Scaling/Basis Record

Basis statement (w/w, w/v, v/v, % solids) with reference temperature; density tables and methods; % solids/moisture methods and TMV; UOM conversion and rounding policy; scale‑dependent corrections (hold‑up, shear, heat transfer) with study references; governed recipe and version history; executed examples with calculations; SPC/CPV charts; label renderings and approvals; deviations and CAPAs; links to Change Control, Lab Analyses, and Mass Balance. House under Document Control with effective dates and approvals.

22) How This Fits with V5 by SG Systems Global

Governed basis & conversions. The V5 platform stores the master basis, density/temperature tables, and % solids methods. It performs conversions centrally and pushes targets to devices—no spreadsheets, no duplicate math.

Device‑tight execution. V5 binds scales, flow meters, and densitometers to steps, calculates temperature‑corrected volumes, and blocks dosing when identity, status, or environment fail. Results stream into the eBMR with full audit trail.

Labels & WMS. Ingredient order and net content panels are rendered from the same basis; verification scanners enforce parity at pack. The WMS stages eligible lots and records movement via EPCIS with serialization where needed.

Quality & improvement. Live SPC/CPV track density, solids, and conversion accuracy; deviations route to CAPA. Bottom line: V5 turns basis from tribal knowledge into governed automation—predictable for Finance, defensible for QA, boring for operators (as it should be).

23) FAQ

Q1. Which basis should be my master—w/w, w/v, or % solids?
Use w/w as the master unless regulation demands volumetric control. If performance depends on solids, manage a solids view in parallel and let the MES adjust carrier. Render w/v or v/v for labels and external specs from the same source data.

Q2. Can we rely on supplier density and % solids?
Start there, then verify. Lot‑test to a sampling plan, trend drift with SPC, and correct execution targets when lots deviate. Escalate via SQM/SCAR if chronic.

Q3. How do we encode qs steps without turning operators into mathematicians?
Author qs logic in the recipe (e.g., “qs with water to 100.00% w/w at 20 °C”), have the MES compute the exact addition from prior steps, and display it at the point of use. Block completion until the computed value is met within window.

Q4. Our labels are volumetric but we dose by mass—is that okay?
Yes, if density is governed and rendered identically in execution and label math. Lock temperature references, apply compensation, and prove parity with routine checks.

Q5. Where do rounding rules live?
In the platform. Set significant figures per component class (macro vs. micro), round once at presentation, and prevent local overrides. Manual edits require reason codes and e‑signatures in the audit trail.

Q6. Do we need PAT to control basis?
Not always. Gravimetric control plus validated lab methods are sufficient for most processes. Inline sensors add speed and stability—use them when economics and risk justify, and validate under CSV.