
Celery juice is the thin, watery liquid pressed from celery stalks.
Watery freshness with a natural salinity, and the salinity is what separates it from any other green juice. It browns and separates within the day, so it is pressed to order or not at all.
Celery salt
Ground celery seed and salt, so it carries the aroma and none of the water. It adds no volume, so it will not stand in for the juice by measure — but a pinch in a sour pulls the flavor together and takes the edge off the green bitterness. Count its salt: it comes along too.
Celery bitters
A couple of dashes bring the aroma back but no volume and no freshness, so it works where the juice was seasoning and not where the juice was the length of the drink.
Cucumber juice
The same watery freshness in the same measure, and it lengthens a drink exactly the same way. What it has not got is the saline edge, so put that back with a pinch of salt or a dash of celery bitters.
Fresh juice keeps a day refrigerated and loses its freshness quickly. Bottled juice is pasteurized, so it lasts longer and tastes notably duller.