Source: https://guthlabs.ai/docs/instruments/culture-media-buffer-recipe-scaler/mechanism/

instrument mechanism / verified-clean

# Culture Media / Buffer Recipe Scaler mechanism

The inspectable method record for Culture Media / Buffer Recipe Scaler, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The exact ambiguity requiring review is that the specification does not state volume units or require recipe_volume and target_volume to be dimensionally compatible. The honest label is appropriate: this is an arithmetic scaling aid and should not be presented as recipe validation or medical advice.

- The formula is correct for linear scaling when recipe_volume and target_volume use the same units and recipe amounts are specified for the recipe's final volume.

- The specification does not define constraints for negative amounts or volumes, nor whether target_volume=0 is permitted.

- The formula does not account for non-linear preparation effects, stock-solution concentrations, density changes, evaporation, or practical rounding; it is only a proportional arithmetic scaler.

## Units and conventions

- recipe_volume and target_volume must use identical units, or one must be explicitly converted before calculating the ratio.

- Each recipe component amount is scaled independently and retains its original unit, such as grams, milligrams, milliliters, or moles.

- The recipe amount represents the quantity required in the stated recipe final volume.

- For a final-volume recipe, component quantities are assumed to scale linearly with volume.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "recipe_amounts": {
      "NaCl_g": 10,
      "glucose_g": 5,
      "water_mL": 1000
    },
    "recipe_volume_L": 1,
    "target_volume_L": 2.5
  },
  "expected_outputs": {
    "scaled_amounts": {
      "NaCl_g": 25,
      "glucose_g": 12.5,
      "water_mL": 2500
    }
  },
  "working": "Scale factor = target_volume / recipe_volume = 2.5 L / 1 L = 2.5. NaCl = 10 g × 2.5 = 25 g. Glucose = 5 g × 2.5 = 12.5 g. Water = 1000 mL × 2.5 = 2500 mL."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

A zero recipe volume produces undefined scaling and should be rejected. The specification also leaves unit normalization unspecified, allowing a severe error: 5 g is correct for 1 L to 500 mL, whereas raw numeric division would produce 5000 g.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/culture-media-buffer-recipe-scaler/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/culture-media-buffer-recipe-scaler/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/culture-media-buffer-recipe-scaler/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`