Mix all the ingredients together and it's done. Adjust the amount of red potato vinegar and grapefruit to taste.
Refer to this ultimate method for peeling grapefruit. (Recipe ID: 1141962)
Story Behind this Recipe
Once when I thought making grapefruit vinegar was too much work, I tried putting grapefruit in pomegranate drinking vinegar, and it was delicious. The pink and yellow color combination is so pretty too. (Translator's note: grapefruit drinking vinegar is grapefruit combined with vinegar and sugar.)