IngredientsVegetables
Knollensellerieceleriac
Apium graveolens var. rapaceum, the swollen root of the same species that gives stalk celery. Rough and beige outside, white and firm inside.
The typical celery smell comes from phthalides. In the root it sits denser and earthier than in the stalks, and it survives long cooking. That is why it goes into Suppengrün, into beef stock, into goulash and into the Sauerbraten marinade, as well as celeriac salad and celeriac schnitzel.
In Mexikoin Mexico
It is called apio nabo and it is not in every shop. City Market carries it, big mercados sometimes.
In the market, apio on its own means the stalks. Ask for apio and you get stalks. Say apio nabo and ask for the root.
Ersatzwhat to use
Stalk celery with plenty of leaf, roughly twice the amount, and cook the leaves along with it. That gets the direction, not the depth.
The stock turns fresher and greener but loses its earthy base. A little more root vegetable and a piece of parsley root make up part of the difference.
Vorsichtwatch out
This is the hardest German vegetable to replace in Mexico. Without it Suppengrün tastes of carrot and not much else.
Root and stalk are not the same thing, even though both are called celery. For a stock you want the root; for a raw side dish, the stalks.