Rinse aid
Not a cleaner at all. It lowers the surface tension of the final rinse so water sheets off instead of beading, which is why it prevents spotting.
In detail
Rinse aid does nothing to the soil on a plate. It is a surfactant released into the final rinse whose only job is to lower the water's surface tension so that it spreads into a thin sheet and runs off, rather than beading and staying put. That single change accounts for its whole effect. Water that beads and then evaporates in place leaves behind everything dissolved in it, which is the spotting and filming people attribute to the detergent; water that sheets off carries the dissolved minerals down the drain with it. Faster drainage also means less water left to be dried by the machine's heat, which is why loads come out drier and why plastics — which hold no heat of their own — benefit most. Two things follow. In a hard-water area rinse aid is doing more work than in a soft one, because there is more dissolved mineral to leave behind. And it does not substitute for dishwasher salt, which addresses the water going in by ion exchange, where rinse aid addresses the water coming out. Glassware that is cloudy despite both is worth testing with a brief acid soak, because a mineral film dissolves and etching does not.
Properties
- pH
- Mildly acidic
Why
- Rinse aid is explained by Wetting and surface tension
- Rinse aid is explained by Evaporative deposition
Sources for this page
Sources
Owner's Manual: Dishwashers GSD4500, GSD4800
GE Appliances · Manufacturer documentation
Relied on for: That the manufacturer addresses water conditioning, filming and spotting on glassware in the course of specifying detergent and rinse products. (states this directly)
Verification: a person has read the passage relied on.
Read on — 'Caring for the dishwasher' and the film, cloudiness and marks entries in Troubleshooting Tips. Supports the claim as stated.
Kirk-Othmer Encyclopedia of Chemical Technology
John Wiley & Sons · Reference work
Relied on for: That surfactants reduce interfacial tension, which is what allows a rinse to sheet rather than bead. (background and mechanism only)
Verification: the work exists and is described correctly. Nobody has yet read the specific passage.
Last reviewed by a person on .