hey my boy has had his z strains colonizing for about 3 weeks now. he says that only like 70% of his cakes are colonized and that one of them has an off-white / TAN color? is this cake still good? or is it bad? hope to be getting some pictures up soon.... ima go over tomorow and checkem out

Most likely they are bad. Post some pics. Usually you want them to be a pearly white color. Some yellow white pee looking stuff is okay and same goes for a clear slime. Those two things are the mushroom antibiotic cells fighting germs. Usually as long as your culture smells fresh, slightly earthy, and clean (think a spring like) then you have a healthy culture.

Follow this guys video series to the letter next time and you shouldn't have any trouble (he's growing edible legal mushrooms) but the same process works for cubes too.

Also in the future your friend may want to grow in a monotub. That's 1. way faster and 2. you get a shit ton of more mushrooms for the same amount of work and time. Cakes really are the worst way to do the job.