title_body: What do I need to start cold-brewing?
upvoted_answer: There are two ways to start with: plunging and dripping.
  
  
  Plunging is to mix water with ground coffee, and let the mix sleep slowly.
  Dripping is the same as classical hot-water dripping, except the speed is much slower.
  
  
  The slowly / "much slower" part means about 8-12 hours, depending on the quantity of ground. For example, I use 400mL/14oz and 40g/1.5oz of ground on an 8 hour drip.
  
  The beans should be quite finely ground, as cold water does not penetrate the ground as well as hot water.
  
  @henryJ exposed plunging in detail. As for dripping, it is possible to use a standard filter stand and paper filter.
  
  The hard part is to drip water slowly. There are cheap devices on the market. An alternative is to get one of those flasks used in chemistry class (a new one, never try with a used one---chemistry is scary). The cheapest way is probably to get an empty plastic bottle, put the cap on, use a needle to make a tiny hole in the cap, fix the bottle upside down above the ground to start dripping. The goal is for the water to pour drop by drop, at a rate of about 1 drop every couple seconds.