
Horseradish sauce is a prepared condiment of grated horseradish root in a creamy or vinegared base.
Pungency, salt and body arrive together here, and a substitute rarely brings all three. Body is the one to watch: without it a Bloody Mary reads thin however hot it is.
Prepared horseradish
Grated root with vinegar and salt, no dairy: sharper and thinner. In a Bloody Mary it hits harder and gives none of the creamy softening — start with about half as much and adjust to taste.
Wasabi
The burning compound is the same and it hits the nose the same way; only the plant differs. Most bar wasabi is horseradish dyed green in any case. Worth knowing that most commercial wasabi is dyed horseradish, so the swap often goes in a circle, and either way the heat fades fast once it is in the drink.
Refrigerated and closed. It does not spoil quickly but it goes quiet quickly, so an old jar needs a heavier hand or replacing.