You buy in one unit and cook in another. This page is how NexReps gets from one to the other without a calculator and without a guess.
The default
Every ingredient has a purchase unit — what you buy it in. Litres, kilos, cases, each.
In a recipe, the unit dropdown offers units of the same dimension as the purchase unit. Buy in litres, get volume units. Buy in kilos, get weight units. NexReps knows the standard maths between them.
Most of the time this is enough and you never open this section.
Crossing dimensions
The common case: you buy in litres and cook in grams.
Volume and weight are different dimensions. There is no universal conversion between them — a litre of cream, a litre of oil and a litre of honey do not weigh the same. So grams will not appear in the dropdown for an ingredient bought by the litre, and NexReps will not invent a number.
You know it. It is on the carton, or on a scale. Tell NexReps once.
Same for the units that have no standard size at all: grams in a bunch of coriander, portions in a case, millilitres in "each". No rule exists. It depends on the product, the supplier, sometimes the season.
Add Recipe Unit
Recipe unit — what you want to be able to use in recipes.
1 [purchase unit] = ? [recipe unit] — how many of them fit in one of what you buy.
Add.
The unit now appears in recipe dropdowns for this ingredient, and NexReps can cost anything measured in it.
Read the direction carefully
The field says 1 L = ? UNIT. It is asking how many recipe units are in one purchase unit.
Buying in litres, cooking in grams: how many grams does one litre of this weigh? For cream, roughly 1010. For oil, closer to 920. Weigh it if you are not sure — a guess here becomes every cost downstream.
Get this backwards and every recipe using the ingredient is wrong by a factor of a thousand. The recipe will not complain. It will just cost a fraction of a cent, or a fortune.
Check one recipe after adding a conversion. If the cost is off by a suspicious round number, the conversion is inverted.
It is per ingredient
A conversion belongs to one ingredient and nothing else. The density you set for cream says nothing about oil. A bunch of coriander says nothing about a bunch of parsley.
That is correct — none of these are standard. But it means you set them one at a time, and an ingredient with no conversion simply will not offer that unit.
Recipe Units on the detail page
Recipe Units — 0 custom means no conversions have been added. The dropdown offers the defaults only.
Every conversion you add appears here, and the count goes up.
When to bother
When the dropdown does not offer the unit you cook in.
If you buy by the litre and your recipe is in grams, you need a conversion — the dropdown will not have grams. If you buy by the kilo and cook in grams, you do not: same dimension, NexReps already knows.
The rule of thumb: if the unit is missing from the dropdown, that is NexReps telling you it needs a number only you have.
Next
Wastage — the difference between what you buy and what reaches the plate.