Maxware Reusable Refillable Coffee K-Cup Filters, 4-Pack

If you own a Keurig or other single-cup coffee maker, it’s probably hard to imagine going back to an old drip-style machine. Since the late ’90s, these units have been popular in coffee-loving households for a variety of reasons: They deliver that essential cup of morning joe quickly and easily, with consistent quality thanks to the exact portions of coffee grounds in their K-Cup capsules. And because the capsules are mostly disposable, there’s little to no cleanup.

But for some, these same conveniences are also a liability. No matter how many flavors your pack of K-Cups has, you’re still limited to the same old ones — and none of them will be fresh ground coffee. And then there’s the environmental impact: Drink just a couple cups a day, and all those discarded capsules add up to a lot of waste. Keurig and other top manufacturers did eventually start making their disposable K-Cups out of recyclable plastic, but you still need to go through the trouble of cleaning out your pods before disposing of them — and even then, it’s debatable whether many recycling facilities will be able to process them.

Enter the reusable K-Cup. These empty containers contain filters that you can clean and use again and again, eliminating the need for throwaways. They all contain a lid that you can remove, allowing you to fill the capsule with your choice of coffee, fresh ground or otherwise.

Since you won’t be throwing them away, you won’t need to worry quite as much about their recyclability. Even so, the materials do matter. Most K-Cups in the low-to-middle price range will be made of plastic. Check that the plastic is free of BPA, an industrial chemical that can leach into foods and liquids, potentially affecting your hormone levels. Another chemical to watch out for is DEHP, a possible carcinogen. If the filter portion of the K-Cup is made of metal, make sure that it doesn’t contain lead.

Some K-Cups on the higher end will be made entirely of stainless steel or another metal alloy. Whether that affects the final product or not depends more on the construction of the filter, but you can bet that metal K-Cups will last longer.

K-Cups of both types might include gold plating on their steel filters as a selling point. Studies are mixed on whether that gold allows more antioxidants to drip down into your cup, but that’s the contention. And since gold is chemically inert, it certainly won’t hurt the taste.

Since convenience is why you bought a single-serve coffee maker in the first place, you’ll want K-Cups that are easy to clean. Will a good rinse suffice or can you expect a buildup of residue over time? Are the capsules able to be added to an automatic dishwasher? Those are questions you may want to check the reviews for. Some reusable K-Cups can technically be classified as dishwasher safe, but repeated washings may wear them out faster. Steel K-Cups are typically safe, though.

Finally, triple-check that your K-Cups are compatible with the coffee maker that you use. Keurig makers alone have a ton of different models, and different units will use different sizes of K-Cup.

Permanent filters such as those on reusable K-Cups can have one tricky feature that takes some getting used to, especially if you like your coffee ground finely. The filter mesh is designed to be easily cleaned, and that means the holes in it are liable to be bigger — which means coffee grounds in your coffee. Luckily, this can easily be dealt with. Either start getting coffee in a coarser grind, or add a paper filter into the K-Cup. Some brands even come with add-ons that will fit just right, though it will be easy enough to make one from a standard coffee filter.