The water is normally kept at room temperature, but chilled water is also used. The grounds are filtered out of the water after they have been steeped using a paper coffee filter, a fine metal sieve, a French press, or felt, in the case of the "Toddy" brewing system. The result is a coffee concentrate that is diluted with water or milk, and is served hot, over ice, or blended with ice and other ingredients such as chocolate.[10]
As noted here, numerous studies have highlighted the potential health benefits of caffeine. Meanwhile, centuries of caffeine consumption and extensive study of the ingredient further reinforce its safety. In other words, the billions of people who routinely consume caffeine can continue to do so with confidence and the knowledge that the ingredient may even enhance health.
A 28-year study, eventually published in 2017 in Alzheimer's and Dementia, the journal of the Alzheimer's Association, determined that four to five cups of a coffee a day – a level deemed "moderate" – led to a decreased risk of dementia during that time period. Those who drank coffee in moderate levels had less medial temporal atrophy, which is linked to Alzheimer's disease, compared to those who drank three or fewer cups a day, including those who didn't drink any.