Wash the red peppers well and core them.
Mix the water, vinegar, oil and sugar in a pot. Leave to come to a boil.
Submerge the peppers in lots into the marinade and keep them there until they change color.
Take them out to cool, then pack tightly in 1 jar of 12 1/2 cups (3 L) or smaller ones, while putting cleaned garlic cloves, pieces of celery and black pepper in between them.
Top off with the cooled and strained marinade. Close with caps and sterilize for 10 min.