It is preferable that the coffee should be organic without chemical products. But it also to be cool. You need then to blend 2 cup of organic coffee using the coffee cup this is before using your shampoo.
Use what you get and during an hour you let the mixture aging and your hair will get chocolate color.
An original old advice is to wash your hair with shampoo before applying the mixture and leaving it for 20 minutes.
For setting the color, your hair should be rinsed with apple vinegar cider.
The final point is to use warm water if you are not satisfied with the results.