Hand tempering vs machine tempering

Same crystallography, different control. A machine holds the curve; a hand does not, which is why batch size decides.

Side by side

	Hand tempering	Machine tempering	Why it matters
Working window	Minutes. The chocolate cools and thickens continuously.	Indefinite. The machine holds working temperature.	This is the decisive difference for volume. Hand tempering coats maybe two dozen pieces before the batch needs reworking.
Minimum practical batch	A few hundred grams.	Usually one to three kilograms — machines need a minimum charge.	A machine is useless for a small batch, which cuts both ways.
Consistency across a batch	Drifts. Later pieces coat more thickly as the chocolate cools.	Uniform from first piece to last.
Crystallography	Identical. Both are producing Form V.	Identical.	A machine does not temper better. It holds the result longer, which is a logistics advantage rather than a quality one.

Home and small-batch work. Seeding with tempered chocolate is reliable and needs no equipment beyond a thermometer.

Any production run past a couple of dozen pieces, and any operation where consistency across a batch is commercial.

TemperingSet against Machine tempering, with the practical consequence of each difference.
Machine temperingSet against Hand tempering, with the practical consequence of each difference.

ChocolateHQ editorial synthesis — ChocolateHQ(citation identity confirmed; passage not re-read)
The Science of Chocolate — Royal Society of Chemistry(citation identity confirmed; passage not re-read)