About a month and a half.... I've already used it for 20 gallons worth and I'll be making a starter this week or next week with it to do another 10 gallons with some of it.... It settled out funny so I may actually be posting a pic with questions... I'm still new to this yeast washing thing but thus far it has saved me about 20 bucks!
Courage les garçons, et patience, vos femmes vont finir par apprécier la bière !