The Filter. We started out by engineering a new filter designed specifically for the cold-brewing process. This is not your run-of-the-mill cheap mesh filter designed to brew hot coffee and just repurposed for cold brew. Instead, we built an entirely new filter from the ground-up using etched 18/8 (Type 304) stainless steel construction that's lightweight but shockingly sturdy, while being a total cinch to clean. Most importantly, our filter features 200 micron holes that allow water to circulate at an ideal rate for steeping coarse grounds and making stronger cold brew. You'll taste the difference. This filter also contains no plastic parts, and there are no disposable paper filters or reusable felt ones that are a pain to wash and end up costing you money to replace later. Those paper/felt filters will just soak up all the flavorful oils that are the hallmarks of good coffee anyway, so you won't miss them.
The cap. A patent-pending, FDA-approved, food-grade silicone cap allows the filter to be fully-nested inside a Mason jar or water bottle, without interfering with the container's natural seal. As a result, your coffee stays both leakproof and airtight as it brews. An airtight container prevents oxidation (aka the "coffee killer"), which means you'll end up drinking better-tasting coffee. The cap's shock-absorbing design also protects the metal filter from dents and rattles, helping ensure it can last for years.
The Extendable Base (*found on the Rumble Go only*). The Rumble Go's silicone base features 11 different height adjustments that extend the filter by up to 1.5" so it can fit a wide range of popular 16-32oz wide-mouth bottles. The universal design means you can keep using your favorite water bottle or repurpose an old one that's fallen out of use.
The Mason Jar (*for the Rumble Jar only*). An ideal 3-in-1 brewing + drinking + storage vessel with a legendary seal. Our patent-pending design ensures that this seal stays intact, allowing your coffee to stay fresher since the jar remains airtight and resistant to oxidation. A good seal also keeps it from leaking all over your hands and kitchen.
Want to see it in action? Watch our 92-second video
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