Why does hollandaise break more easily than mayonnaise?
They're built on the same emulsion trick, but hollandaise has an extra way to fail that a cold sauce like mayonnaise never has to worry about.
The kitchen answer
Hollandaise can break the same way mayonnaise does (fat added too fast), plus a second way unique to it: heat coagulating the egg yolk's protein before the sauce has finished emulsifying, which curdles it instead of just splitting it.
What's actually happening
Both sauces rely on lecithin in egg yolk acting as an emulsifier, physically holding fat droplets suspended in a watery base. Add fat faster than the lecithin can wrap around the new droplets, and they coalesce back together instead of staying suspended -- a mechanical failure, fixable by re-emulsifying into a fresh yolk.
Hollandaise adds a second, independent failure mode: it's made warm, over gentle heat, which puts the yolk's proteins within range of coagulation. Too much heat, and the proteins start to set solid mid-emulsion -- the sauce doesn't just split, it curdles into visible bits of cooked egg suspended in butter, a structural change rather than just a mechanical one.
What does that mean for your recipe
A mechanically split hollandaise (thin, greasy, but not visibly curdled) can usually be rescued the same way as mayonnaise -- whisked slowly back into a fresh yolk. A curdled one (visible cooked flecks) can't be, for the same reason a curdled custard can't be un-curdled -- the protein has already set, and no amount of whisking undoes coagulation.
What can go wrong
- Direct heat instead of a double boiler: makes it far easier to overshoot the yolk's coagulation temperature before noticing.
- Butter added too quickly: the same mechanical splitting mayonnaise suffers from, independent of temperature.
- Sauce held warm too long after finishing: residual heat can still push proteins toward coagulation even off the direct heat source.
- Treating any "broken" hollandaise the same way: whisking a curdled sauce into a fresh yolk won't fix it the way it fixes a merely split one -- the cooked egg bits are still cooked.
Try it yourself
Same hollandaise, pushed to fail two ways:
- Make one batch normally, adding butter too quickly on purpose to split it mechanically.
- Make a second batch, but hold it over heat noticeably longer and hotter than normal until it visibly curdles.
Watch for: the first batch looking thin and greasy but uniform, while the second shows visible small curds -- then try re-whisking each into a fresh yolk and watch only the first one recover.
Go deeper
Hollandaise sits right at the intersection of two mechanisms this site treats separately -- emulsification and coagulation -- which is exactly why it has a narrower margin for error than either a cold emulsion (mayonnaise) or a fully cooked custard on its own.