Use any amount of wheat berries you'd like, but consider this a good starting point. It's a good amount to add to a loaf of bread.
Add the wheat berries to a clean jar and cover with cool water. Soak for about two hours, or up to overnight.
50 grams (¼ cup) rye or wheat berries, Water
After soaking, drain well. Set aside in a cool, dark place, like the corner of a kitchen counter, and cover the jar with a lid.
Rinse as often as you think of it, but at least once or twice. After about 24 hours, you should see sprouts forming (little white tails on the grain). Your sprouted grains are now ready to use.
Don't let the sprouts get too long. It makes the grain taste bitter. Refrigerate for another day if needed before using.
To dry your sprouted wheat, rinse in a fine mesh sieve and dry as much as possible before turning out onto a tea towel. I place the tea towel on a large baking sheet to contain the grains. They should dry fully at room temperature after a day or two but you may need to use a fan or dehumidifier if your home is humid. You can use a dehydrator if you have one.
Once fully dried, store in a sealed container in the refrigerator for up to a month or freeze up to six months.
To mill your sprouted grains, dry fully first and then run through your grain mill or other tool that you can use to grind them. Keep sprouted grain flour in the refrigerator.
Notes
Some people argue that dried sprouted grains and sprouted flour last longer than un-sprouted but I store all my grain and flour in cool, dark places in any case.