207 From scratch
(PW) from the very beginning, starting with raw materials
This chocolate was not made from a cake mix, she made it from scratch.
(free) From the very beginning
to start (again) from the very beginning; also, to start without resources.
(phraseFinder) Begin (again) from the beginning, embark on something without any preparation or advantage.
Origin
'Start from scratch' is an expression which has altered slightly in meaning since it was first coined. It is now usually used to mean 'start again from the beginning' - where an initial attempt has failed and a new attempt is made with nothing of value carried forward from the first attempt (as opposed to 'made from scratch' which means 'made from basic ingredients').
In the late 1800s, when 'start from scratch' began to be used it simply meant 'start with no advantage'. 'Scratch' has been used since the 18th century as a sporting term for a boundary or starting point which was scratched on the ground. The first such scratch was the crease which is a boundary line for batsmen in cricket.
John Nyren's Young Cricketer's Tutor, 1833 records this line from a 1778 work by Cotton:
"Ye strikers... Stand firm to your scratch, let your bat be upright."
It is the world of boxing that has given us the concept of 'starting from scratch'. The scratched line there specified the positions of boxers who faced each other at the beginning of a bout. This is also the source of 'up to scratch', i.e. meet the required standard, as pugilists would have had to do when offering themselves for a match.
Scratch later came to be used as the name of any starting point for a race. The term came to be used in 'handicap' races where weaker entrants were given a head start. For example, in cycling those who were given no advantage had the handicap of 'starting from scratch', while others started ahead of the line. Other sports, notably golf, have taken up the figurative use of scratch as the term for 'with no advantage - starting from nothing'.
The Fort Wayne Gazette, April 1887, contains the earliest reference to 'starting from scratch' that I can find, in a report of a 'no-handicap' cycling race:
"It was no handicap. Every man was qualified to and did start from scratch."