Working volume
By the end of this lesson
- Distinguish vessel capacity from working fill
- Use actual fill in preparation planning
- Record fill consistently across a run
Examples use a decimal point; a comma groups thousands.
See it
Working volume is the volume actually placed into each culture vessel. It is distinct from the vessel's total physical capacity. A recipe scaler needs the working fill because that determines how much medium the run actually consumes.
Understand it
Distinguish vessel capacity from working fill
Record fill volume per vessel.
Working volume is the medium actually placed in a vessel, not the vessel's total capacity or headspace.
Use actual fill in preparation planning
Use the same unit for vessel fill and total-volume calculation.
Preparation volume follows how much medium the vessels consume, so use the planned actual fill.
Record fill consistently across a run
Changes in working fill can affect both total media and vessel environment.
Multiply vessel count by working fill: 10 × 35 mL = 350 mL before overage.
Worked example
A 250 mL jar is filled with 35 mL of medium. Its working volume is 35 mL. For 10 such jars, plan 350 mL before overage, not 2,500 mL based on physical capacity.
Explain your decision before opening the worked reasoning below.
Show the worked reasoning
Working fill is relevant to preparation quantity and to the physical culture environment.
Equal physical capacities do not imply equal working fills or equal total preparation requirements.
Do not use nominal jar size as a substitute for actual working fill.
Try it
What is the base requirement for 10 jars at 35 mL?
Use the worked example above to explain your answer in your own words before taking the quiz.
Lesson quiz
Assessment version: 2026-10-15-v2. Previous reading-completion markers are retained. This revised quiz has its own result.
Apply it
Use the worked example to write a short decision record: what did you observe, which rule did you apply, and what would you check before acting?
Completion marks reading progress, not a quiz pass or professional certification.