Black Berkey Filter Element — What’s Inside…

Ever since I was young, I’ve been afflicted with the desire to take things apart. To see how things work. I suppose that’s what eventually led me down the career path of technical/engineering. Given my affliction, and since I have a Berkey countertop water filter system, I’ve wondered what’s inside those black berkey filter elements.

Well today, I sliced one open…

You may be saying, “Wow, that’s an expensive impulse! Those filters aren’t cheap!”

No, I didn’t destroy a new filter! Awhile ago I had purchased another set of black berkey filter elements since my original set was many years old, and had filtered many thousands of gallons of water. So, perfect opportunity to slice one open…

Note – It’s not how old the filters are — what matters is how much water they have processed. Each filter is said to purify about 3,000 gallons. So, that’s 6,000 gallons for a set of two (which is what’s inside my Berkey).

Do you want to see what it looks like inside? Here’ ya go…

Inside A Sliced Open Black Berkey Filter

cross section slice of black berkey filter element

Here’s a closer photo of the black material:

close-up photo of black berkey filter element material

The following dimensions aren’t exact. But the overall diameter of the cross-section is about 2-1/4″, while the inside diameter of the ‘hole’ is about 1-1/8″.

Here’s another picture, this one looking down the inside towards the bottom – where the filter is normally secured to the upper water chamber. You can see a spoked support structure at the bottom, helping to stiffen that part of the element – where there are more stresses while assembling.

Black Berkey Filter Element Micro-Pores

I don’t know what the “secret sauce” is, but it looks like carbon. When I cut it open with a hacksaw, it produced extremely fine black carbon powder. There’s other “secret” stuff in there, but that’s their secret I suppose.

They say that the micro-pores are self-sterilizing. You can’t see the pore size with your eyes (of course). They’re incredibly small. So small that pathogenic bacteria are simply not able to pass through them.

The media within the black berkey filter elements remove contaminants by a surface phenomenon known as “absorption”. This results from the molecular attraction of substances to the surface of the media.

Black Berkey Proprietary Absorption

They say that their purification elements are impregnated with proprietary “absorbing” media. “It promotes IONIC absorption of pollutants within the micro-porous elements.”

Long Contact Period

Another reason Berkey systems are so effective in removing contaminants from water is the very long “contact period” with the filter media. Water molecules pass through the “tortuous path” structure of the filter /purification elements drawn by gravity, and stay in contact with the media for a long period of time. This allows the filter media to be more efficient in capturing contaminants.

For example, if you were to hurl 100 steel ball bearings at a large magnet, some would stick but most would bounce off. However, if you were to walk over and gently place the ball bearings on the magnet most, if not all, would adhere to the magnet. Berkey systems fully utilize this principle.

USA Berkey Filters – The Berkey Guy

So, time to plug my advertiser who has been with us since the beginning. If you’re in the market for a set of replacement filters, or a complete system, I do recommend them. Lifetime warranty too.


[ Read: Why You Should Buy A Berkey Water Filter From The Berkey Guy ]

[ Read: Black Berkey Filter Elements vs. White Ceramic ]


  1. Silver? Would be a reason for the $$$. Love my Royal too. Going to get the stainless glass spigot. Yes will mention MSB.

  2. Cool,,,

    I know you are a berkey guy,

    But im curious how the knockoffs compare, would be interesting to do a straight up comparison, or perhaps you or one o the MSB family know of a straight up comparison?

    Interesting, never would have guessed they were hollow

    1. ken, do you get any black water from the filters when you change them out? refrigerator carbon based ice maker filters are bad about that for the first gallon or so. i always purge them in a bucket when i change them out before making the final connection.

  3. Bought my Big Berkey probably 15 years ago. They threw in two Berkey Sport Bottles as a bonus. I’ve never used the sport bottles, they reside in the side pouch of my get home bags.

    Probably has nothing to do with it, but I’ve not drank a drop of water, cup of coffee, tea since buying that the water didn’t go through the Berkey first, and I have not suffered any seasonal bugs, colds, flu or stomach problems since.

    I can think of no other prep as important. I know money is tight right now and prices on Berkeys have increased substantially. Y’all know I believe in the importance of have a good, reliable firearm…I believe peace of mind that your water is safe is similar in importance.

    1. can a person get immune to giardia and cysts in the water? growing up, water was water west of the rockies. my friends, scout masters and i drank from what we could find, seep’s, springs, creeks, lakes and the few rivers. we never heard of bugs in the water back then in the 60’s and none of us ever got sick, just scooped it up and drank it. we may have just been lucky. the only bad water was well water that had a lot of gypsum in it. people who were not use to it would come to visit and be on the pot for a week…. we called it having the gyp’s. : ) it was funny.
      didn’t bother us, we lived off of it and were use to it.

      1. Scout,
        Back in the 60s Guardia was not well established in the West. I did the same as you hiking/camping in the Sierras and deserts. Seems sometime in the 70s it got a foothold and was spread by beavers and deer. By the late 80s early 90s drinking straight out of a stream with your Sierra cup became an issue. Maybe Calirefugee can shed more light on it. And no, you can’t develop immunity to it to my knowledge.

      2. When I was stationed at Subic Bay Naval Base Philippines, the main gate and the town of Olongapo was separated by what was commonly known as “Shit River”. Literally the waste from the open sewers in town flowed into this river that emptied into Subic Bay and it reeked but you got used to it. When you crossed the bridge there were kids in banca boats (canoes) that would dive in, swim around and get pesos people threw to them.

        We called them the “Shit River Navy” because a couple of them wore sailor hats and one had “Joe” written on it. They were there everyday, 103 degrees, rain or shine for the nearly three years I was there and never appeared sick so I guess they were immune. Just like the open air markets where flies covered the meat and refrigeration was rare you had to really watch where and what you ate. If you or I fell into that river there is no telling what diseases we would contract or how fast we would die.

      3. scout, In my travels I learned giardia was a parasite. Picked up by ingesting feces-contaminated food or water. Got real sick a couple times from eating out in the developing world. Turns out just because the food is hot doesn’t mean the plate isn’t contaminated. Reactions vary, but a fully immune response doesn’t seem to be possible.

    2. Also love my royal, I use it daily, about every three months I take a wet sponge pad and wipe the outside of the filters to remove any sludge or whatever that might build up, the cleaner the water that you put in determines the cleaning cycle. Also I have used after market black filters a decade ago, they are JUNK. I put a travel berkey in my camper and purchased 3 extra sets of black filters last year, glad I did because of the price increases. Suggest you keep a metal replacement spigot on hand as the plastic ones are very fragile, you can buy a nice metal one on Amazon for about 10 dollars.

      1. Realist,
        Hope you camper is heated in the winter. If not, those Berkey filters are liable to freeze and break if they have ever been wetted. Bad thing is you might think their okay, but if cracked you’ll get unfiltered water in with the good, basically contaminated. Once used, it’s hard to dry out filters enough to keep them safe from freeze cracking. Same thing goes for lifestraw and other portables, once used must be protected from freezing. Just a reminder for folks.

        1. It’s a new unused unit, but thanks for mentioning the freeze thing.

  4. Reply to Scout, Miner Jim and Romeo Charlie: Living in a first world/industrialized nation, our gut is not used to processing water with lots of microorganisms in it. If we were to ingest water with bacteria in it, we would probably get real sick. Lots of talk of giardia here on this particular site. I would like to remind folks that there are a lot of microorganisms other than giardia out there that will make people sick like campylobacter, cholera, shigella, Knowing all of that and realizing that I was not paid to sit at home on the toilet, I used a filter religiously when not drinking from the tap at my park. That or I boiled my drinking water yielded from mountain snow. As a ranger, I never took microbiology until after I worked off grid.
    Prior to working as a ranger/fire fighter, I cooked for other people both as recreation and for a paycheck. I washed my hands before and after I processed food and grew up helping my mom (worked for a chef later on) in processing raw ingredients into good food. We did not know the names of the microorganisms that made people sick. We washed our hands and kept our kitchen clean to prevent people from getting sick. I’ve never been to culinary school. I never took a cooking class. I am proud to say that nobody got sick from the food I prepared.
    National parks west of the Sierra Nevada mountains in California are high traffic zones. People get sick from drinking untreated water all the time. There was a lot of flagyl being passed out from clinics and pharmacies along the Sierra foothills. For more info, look up water borne illnesses and take your pick of pathogens.

    1. Outstanding advice and info. When I was a trail worker on the AT water safety, personal hygiene and camp/kitchen cleanliness before, during and after food prep was as important as tool safety. We would be out on the trail for 5-6 days and if someone got sick they could be miles away from a road crossing and trying to hike out with dehydration, lose bowels, heat and weakness is a recipe for serious medical complications.

      Earlier this summer I was walking along one of the “Pure Spring-Fed Mountain Streams” on my property and found a dead fawn in the middle of the creek. You never know what’s upstream or hiding in that “crystal clear” water.

    2. Calirefugee,
      Agree there are many bugs in water to make you sick. I (& Scout) remember back when giardia was not an issue. Do you know anything about the history of its spread in the West? Thanks, just being curious.

  5. Further info on drinking treated water: When large numbers of Americans went to Afghanistan years ago, many took note that the older devout members of afghan society did not seem to get sick from water borne illnesses. Over time, the observers came to realize that most everybody within that society drank tea prepared from boiled water. As far as young filipino kids playing in polluted water, they may be fine today but what about a year from now? I would submit an answer that those kids playing in polluted water sources are strongest of the lot and many of their cohorts did not survive to live to that age. Stories like that just make me want to go wash my hands and do laundry.
    Maybe a decade ago, in one of my first postings on this site, the experience of living and working off grid for a number of years taught me many things. One of the first things was that in order to cook, clean, do laundry and to clean myself took a lot of work, energy and preparation just to stay clean, dry, well fed and hydrated. When I came out of the mountains, I enjoyed: ice cold drinks from the fridge or ice chest, a hot cup of coffee prepared by some body other than me. A meal on ceramic plates with cloth napkins, Air conditioning within a supermarket loaded with food. (bring your wallet/leave the rifle and fishing rod in the truck). Pretty ladies that wore make-up other than sunscreen and shaved their legs. A hot bath or shower. My weekly treat was to go “into town” where I would find a strip mall with a grocery store, coffee shop that served good home style food and a Safeway market all within walking distance of each other.

  6. I use a Zero Water filtration system. I have a plug in RO filter, but I rarely use it, too limy here. You have to de lime it quite often. The Zero Water filters better then the RO . It really does test zero on the TDS meter.

    The reason I never purchased a Berkley, is, they can’t deliver one to my state. How ridiculous. Backwards state,, Good is bad for you and their frankenfood is just fine. I asked my senator to label our food but he claimed that it was just fine, according to the science. Trust the science, Monsanto trust theirs.

  7. Reply to MinerJim and Scout on hx of giardia in the west: Unknown. I remember reading about it in backpacker magazine back in the mid to late 70’s. It was acknowledged to be in the water by the 1980s by the NPS. Unsubstantiated rumors were it was brought back to the US by soldiers that served in Viet Nam where it was acknowledged to be endemic in the freshwater sources over there. All veterans of Viet Nam that drank water in the field and were issued halizone tablets relate that the water over there was contaminated and the rice paddies were fertilized with excrement from humans and animals.
    Living off grid and purifying my own water made me very interested in municipal water systems in the communities I lived in ever since. Classes in microbiology and chemistry added to my list of things to be wary of.

  8. Three things I looked for when coming out of the hills and going to town: Laundramat, Cafe or diner that served homestyle cooking and the waitress calls you hon’, a grocery store or Safeway (back in California back in the day). all establishments within walking distance to each other. Odds are, I would swing by the hardware store before I left town to go back to the hills again.

  9. Mimison, re “Have you heard Berkey is in the courts for false advertisement. Many lawsuits against this company. They lied the whole time. They are not even NSF Certifide.”

    If you’re not just trolling and are seriously concerned, it’s time for you to do some homework. First there are not many lawsuits. There is one class action suit filed by three Californians, even though the company that makes Berkey does not market to or sell all products directly in CA. (See Latest activity I could find is that the case has been transferred to TX by CA judge due to jurisdictional issues. NSF certification is irrelevant to this product. Read product literature for complete explanation. Start here: Then there is a lawsuit filed by a late-comer to the commercial water filter business trying to hamper a competitor. Frivolous lawsuits to harass and gain notoriety and a payout are common. Lawsuits, until fully adjudicated through all appeals are not indicative of any wrongdoing. I’ve always believed that if God had wanted man to think, God would have given him a brain.

    1. TMAC Like to remind people that those like yourself in a lawsuit always have your attorneys investigate the total insurance payout clause amount that the defendant is covered for…….and always remember if you pursue a trial the amount awarded to you in a judgment directed settlement usually nets about 25% of the actual award by the time costs and labor are needed to collect it. Good luck to you my friend.

  10. Soul….I made mine from two old food grade plastic buckets with the screw on lids, cheaper then the steel pots and i believe more sanitary and no fingerprints on the outside to clean up. Have two berkeys but they are a pain to keep the outside looking nice.

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