Where it goes wrong
Mental arithmetic under pressure, mixed units (grams, decilitres, pieces) and the original being overwritten with the scaled version. After that nobody knows what the base recipe was.
Calculate from the yield
Write down what each recipe makes: 0.5 litre, 40 portions or 50 pieces. Then you do not calculate “times fifteen”, but with what you need.
Keep the original
Scale a copy or only convert on screen. The base recipe stays exactly as it was, for next time.
Careful with gels and doughs
Gelatine, agar, raising agents and salt do not always scale one to one in practice, especially in large quantities. Always taste and test a big batch before relying on it.
In Savour you enter the yield you need and Savour converts every quantity. The original recipe stays as it is.