Soak the bacon for at least 1 hr. in warm water—if very dry or highly salted longer is needed, and the water should be changed. Scrape the underside and the rind as clean as possible. Put into a pan with cold water, just to cover. Bring slowly to the boil and remove any scum. Simmer gently until tender, allowing about 25 min. per lb. and 25 min. over, e.g.