Water sources can contain contaminants that impact your long term health, the taste & smell of the water and other microbiological contaminants that can actually make people sick shortly after drinking. Fortunately, there are water filtration products that remove many of the impurities from water. These filters often use activated carbon. Activated carbon is a form of carbon processed to have small, low-volume pores that increase the surface area available for adsorption of contaminants or chemical reactions. Two dominant carbon filter choices are solid activated carbon blocks and granular activated carbon filters.

Filter Design

Granular activated carbon filters have loose granules of carbon that look like black grains of sand. These black grains of carbon, are dumped into a container and the water is forced to travel through the container to reach the other side, passing by all of the grains of carbon. Solid block carbon filters are blocks of compressed activated carbon that are formed with the combination of heat and pressure. These filters force the water to try to find a way through the solid wall and thousands of layers of carbon until the reach a channel which leads the water out of the filter. Both filters are made from carbon that’s ground into small particulate sizes. Solid carbon blocks are ground even further into a fine mesh 7 to 19 times smaller than the granular activated carbon filters.

Flow Channels & Less Contact Time 

As water continually pass through Granular Activated Carbon filters, flow channels begin to develop that allows the water to flow around the carbon. Flow channels also develop between the granules, leading to less effective filtration as there’s less contact between the water and carbon. Solid carbon blocks are much tighter and won’t even let through microbial cysts like giardia and cryptosporidium (7 to 10 Microns in size). However, solid carbon block filters are so tight that they can often get plugged up with organic & non-organic matter, forcing owners to replace them on a more regular basis. This is why when you are using a Brita water pitcher filter (granular activated carbon), the filter will keep going and going long after it has stopped removing any water contaminants. 

Carbon Block vs Granulated Activated Carbon 

The granular activated carbon filters are cheap and simple to manufacture, which is why most water filtration companies choose this method for manufacturing (ex: Brita, Woder). Solid Carbon Block Filters on the other hand take longer to manufacture and are more expensive but with this expense, you get superior contaminant removal because the water must take a tortured path through thousands of layers of compressed carbon before it reaches your drinking glass.

Better Filtration

The solid carbon block filters like the one used in the Epic Smart Shield & Epic Water Filter pitchers, remove more contaminants than the granular activated carbon filters due to the larger surface area and the tighter filters, this is why Epic Water Filters has standardized on the solid carbon block design for our water pitchers and our under the sink water filter. Unfortunately, granular activated carbon filters do not do enough to reduce contaminants, this is why they are not used when there is a chance of bacteria or cysts in the water. They are truly not "Epic" so that is why we have passed on this design and let our competitors like Woder, Brita, Pur, and Invigorated Water use these loose packed carbon filters for sub-par contaminant removal.

Solid carbon block filters, on the other hand, have millions and millions of different sized pores that cause the water to take a long slow path to get through the filter, increasing the contact time that the contaminated water has with the carbon. During this contact time is when contaminants adhere to the carbon and are removed from water. This happens during a process called adsorption, the other filtration method that carbon blocks use is called depth filtration where the thickness of the filter comes into play to help remove contaminants as they have to pass through this carbon walls. 

With solid carbon block filters the contaminants are in contact with more carbon for a longer period and therefore have more time to remove stubborn contaminants like lead (Epic Pure Pitcher 99.9% removal), fluoride (Epic Pure Pitcher 97.8% removal), and PFCs (Epic Pure Pitcher 99.8% removal). Carbon blocks can remove chlorine more effectively, eliminate undesirable odors, and removal of endocrine disruptors like volatile organic compounds. The granular activated carbon particles move around, so the filter does not have as much uniformity throughout, unlike the solid carbon blocks.