The quickest way to build a new liquid class is to not build it from nothing. Almost every liquid resembles one you have handled before, and starting from a predefined class for a similar liquid gets you most of the way there before you change a single number. The trick is knowing which existing class is closest, and that means thinking in families.
Group liquids by how they behave, not what they are called
For handling purposes, most reagents fall into a handful of families whose members behave alike in a tip. A class that works for one member is usually a strong starting point for another.
- Aqueous solutions: water, PBS, TRIS, most buffers and master mixes. Low viscosity, well behaved, near-default settings.
- Volatile organic solvents: ethanol, isopropanol, acetone, formaldehyde. Defined by evaporation and dripping, so they want small air gaps and anti-droplet handling.
- Involatile organic solvents: DMSO, alkanes. Organic but not volatile, so they behave more like water on speed while still needing solvent-aware care.
- Viscous liquids: glycerol, oils, bead suspensions. Slow everything down and expect tip-specific tuning.
- Blood products: serum, plasma, whole blood, red cells. Protein-rich and prone to foaming and clots, so they benefit from clot detection and gentle handling.
Pick the closest member, then adapt
When you need a class for a liquid you have not run, find its family and start from a validated class for the nearest member. A new master mix starts from a water or PBS class because it is aqueous. A new alcohol starts from an ethanol class. The starting class already encodes the family behavior, so your adjustments are small and targeted rather than sweeping.
Where family thinking breaks down
Families are a starting heuristic, not a guarantee. A buffer loaded with detergent behaves more viscous than its water cousins; a partially volatile mixture sits between families. Treat the family match as your first draft, then verify against the real liquid, because the point of starting close is to shorten tuning, not to skip validation.
The best starting class is the one for the most similar liquid you have already validated. Family resemblance is a shortcut to good parameters, not a substitute for checking them.