The 27-year-old model insists it's important to get rid of cosmetic products in order to have great skin and the best way to ensure the "grit and grime" has gone is not to rush the removal process.
In an interview with UK Glamour magazine, she said: "If you're going to spend an hour putting your make-up on, or 30 minutes or even just 15 minutes, you should be able to dedicate that amount of time to taking it off.
"That way you get rid of every bit of grit, grime and make-up off your skin."
Jourdan - who has an eight-year-old son Riley from a previous relationship - keeps in shape under the watchful eye of her personal trainer brother, Antoine, and enjoys barre training and boxing, which help her get rid of stress and feel more energised.
She said: "I love boxing, especially because I get to do it with my brother [Kobox fitness trainer, Antoine Dunn].
"My brother introduced me to boxing at Kobox, which is such a fun environment.
"I step into the ring, get my sweat on and feel more energised. It's a fun way for your mind and body to let out stress."
Although the British star enjoys her fitness regime, there are certain exercises that she has to push herself further for.
She said: "I love anything to do with my legs, so squats and lunges I'm totally here for - they are amazing for toning - but I just hate burpees.
"Whenever I do a personal-training session with my brother, he always makes me do them and that's definitely my least favourite type of exercise.
"My brother does not care that I'm his sister when he is training me. If anything he pushes me even harder; he won't give me a day off or let me slack because he knows my potential. I do need that though."