Cleaning out coffee pots and thermoses

We brew beer at home, so we have a product that does a really good job of this, called PBW (Powdered Brewery Wash). Our stainless steel coffee thermoses come out like new. The product description from a site that offers it reads:

PBW (Powdered Brewery Wash) is a patented alkali cleaner originally developed for Coors, now widely used in commercial breweries across North America. Use 1 to 2 ounces per gallon for cleaning kettles, 3/4 ounce per gallon for fermenters, kegs, tanks, and other equipment. Soak equipment overnight in PBW solution; rinse the following morning - no scrubbing required! Will not damage rubber gaskets, soft metals, or your skin. PBW can effectively clean items that can't be reached with a brush or sponge, and is strong enough to remove thick, difficult, caked-on organic soils.

That said, we already have this product. I've been doing some research and it sounds like Oxiclean actually works about as well and you may already have some at home - and if not, you can likely find it more easily.

I use vinegar usually distilled white vinegar running it through the system like making coffee will clean the inside of the machine of buildup and help clean the pot, vinegar is a weak acid, if you need stronger muratic acid that is used in swimming pools to balance the PH could be used but I would dilute it with water and not flush it through the machine just in the pot and thermos. In both cases at least 3 cycles with fresh water after cleaning of the parts cleaned may get the results you want without much work. I have used 30% muratic to clean stubborn stains on tile in the past. Remember of you do use muratic all ways add the acid to the water for safety.

I use homebrew steriliser on my Thermoses and stained coffee-making equipment. This takes off the stains very nicely if you soak and agitate/brush. It rinses off quite well with cold water.

Hot vinegar can also be quite effective as part of the build-up is often limescale. again, soak and brush.

Don't, by the way, do what I tried to do and steam-sterilise the cap of a thermos in the microwave (there was a bit I could only rinse through and not scrub, and I realised how dirty it was). Mine exploded.

In my experience, any strongly alkaline cleaning agent will dissolve coffee gunk nicely.

You can buy fancy cleaning products specifically made and marketed for that purpose, like your "coffee pot cleaner powder", but just plain old sodium hydroxide (soda lye, caustic soda, NaOH) or sodium carbonate (washing soda, Na₂CO₃) solution with a bit of dishwashing detergent mixed in will do the job just as well. Or you can just use dishwasher detergent, most of which are highly alkaline.

Safety warning: It should go without saying, but strong alkaline solutions are caustic. They won't kill you if you touch them, but they can cause irritation and nasty chemical burns if you get them on your skin and don't wash them off ASAP. If you get some in your eyes, despite the goggles you really should have been wearing, also wash it off with lots of water and go see a doctor.

Also, don't use alkaline substances on aluminum, or on anything else that's not dishwasher safe. Steel and glass and most plastics should be fine, though.

After dissolving the coffee stains with the alkaline cleaning solution and draining it, you'll want to rinse your pot with a mildly acidic solution to neutralize any alkaline residues. This will get rid of the soapy taste you complained about.

Dilute citric acid or acetic acid (clear vinegar) should work fine, as will any descaling agent suitable for use with cooking utensils. Just rinse the pot thoroughly with the acidic solution, and then once more with water only, and let it dry.

The acidic rinse will also help dissolve any limescale that might have accumulated in your pot alongside the coffee residue. In fact, if you live in an area with hard water, you might even want to consider a three-step wash: first acid to remove limescale, then alkaline to wash off the coffee residue, and finally mild acid again to neutralize any leftover alkaline cleaning solution. I haven't tested that myself, since the water around here is pretty soft, and so limescale is rarely an issue. But I suspect it might be worth trying.

Also, where possible, simple mechanical scrubbing with a sponge, with or without any chemical cleaning agents, will help a lot in removing persistent coffee stains. (Do make sure to put on rubber gloves before sticking your hands in the caustic soda solution, though!) In fact, for things like coffee cups and spoons, I've found that a good scrubbing with a rough sponge and some dishwashing soap does the job quite nicely. The chemical methods are really only needed in extreme cases, or for hard-to-reach spots e.g. in thermoses where mechanical cleaning would be difficult.

When I worked in restaurants we would put crushed ice, table salt (4-5 tsp.) and some lemon or lime juice in coffee pots to clean them. Swirl it around for a bit, dump out the mixture and rinse well.

I think white vinegar works well also. By itself (running it through a percolation coffee maker) or in place of the lemon/lime juice in the mixture I mentioned.

Other answers have listed vinegar and lemon juice and baking powder. There are products that combine all those things into some kind of super cleanser, and it is… denture cleaner.

One tab of denture cleaner (and of course water) in the thermos over night works just fine.

It should be mentioned that some brands may add some aroma to make your dentures and your breath minty fresh. Stay away from those brands, your coffee or tea will taste a bit funny.

Denture cleanser will also clean your electric kettle and coffee machine.

The typical cleaner that I used awhile back on the office coffee pot (a commercial model Bunn) was a brand name "Dip-It" powder. You would add about a teaspoon or so to hot water, and it would remove coffee residue, and scaling in warmer elements. Yes, I would use it on my thermos too.

It seems that "Lime-A-Way" brand has bought out the product, and reformulated the liquid product. Comments on Amazon indicate it may be hard to find the powder retail, and many people are not happy with the reformulation. A little googling, it's possible that the power form may be offered now for commercial use only by Ecolab, as "DIP-It XP" Their SDS lists the primary component as Sodium Carbonate.

You may want to keep searching.

I use the wonderfully named Puly Caff powder and it does great job of dissolving the oily coffee gunk. It's designed for coffee machines and although I haven't tried it on a cafetiere/thermos it would be worth trying. A large bottle in the UK costs about £7 and I use a teaspoon each time.

The best cleaner I've found for stainless steel and glass when it comes to coffee or tea is Bar Keeper's Friend. I use it to clean high carbon steel knives since they are stainable. The second best cleaner is distilled white vinegar, although apple cider vinegar works as well. In general, light acids are best to REALLY remove the gunk that builds up from coffee and tea without leaving that soapy aftertaste that dish soap does.

One time I had to clean up a Nalgene-like bottle after someone had left milk it in for weeks. That rancid milk smell wouldn't come out of the plastic no matter how many times I washed it with dish soap. I used distilled white vinegar and let it sit in the bottle for about the same amount of time the milk was in there, and after rinsing really well with water, the smell was gone. There may have been the faintest smell of vinegar left, but that was far preferable to me than rancid milk.

Ordinary household bleach will take out the stains; 1 part bleach to 4 or 5 parts water will do the job. Be sure to rinse well with water and be sure it doesn't get mixed with any other cleaning chemicals. I'd use it on a carafe or thermos where I can be sure all surfaces get a thorough rinsing, but would not run it through a coffee maker. For that I'd use vinegar as in some of the other suggestions. BTW, bleach is good for stain removal, but won't do much for lime scale. Vinegar is the ideal choice to get rid of scale.