(psst! if you own a Rumble Jar and not a Rumble Go, then your brewing instructions can be found here)
Step 1: Choose a compatible wide-mouth bottle that you'd like to use for brewing. Then adjust the height of the filter's silicone base so that the filter is as as high as possible without interfering with your ability to screw the cap onto your bottle. It will take a little trial-and-error to find the perfect height.
Step 2: Pour coffee grounds into the filter (coarse grounds are recommended for cold brew, but medium grounds work too). You'll find 3 small notches running along the length of the metal filter. Those are there to help you eyeball how much coffee to use so you don't need to measure precisely. If you're using a bottle with a 16-24oz capacity, try filling grounds to somewhere between the lower and middle notches. If you're using a bottle with a 25-32oz capacity, try filling grounds to somewhere between the middle and upper notches. There's no such thing as a perfect amount, since that will vary depending on your personal taste as well as your bottle's specific dimensions. So feel free to experiment. We also have a FAQ page listing the capacities of our filters, in case those specifics are helpful.
Once you've filled the filter with grounds, just put the silicone cap on the filter, and place the whole thing into your empty bottle.
Step 3: Pour cold or lukewarm water into the bottle and tighten your bottle's cap. Now the fun part! Give it 2 quick "rumbles" (i.e. rotate bottle horizontally twice). This "rumble" step is what agitates the brew, and it's necessary to soak the grounds and kick off the brewing process (that's why we named it a Rumble Go!). Don't forget to do it, but also don't overdo it (no vigorous shaking)!
Step 4: You sleep while it steeps for 8-24 hours. In the morning, just remove the filter and enjoy your cold brew straight from your bottle. Alternatively, if you have no convenient place to put the filter, you can also leave it in the bottle while you drink directly out of it, or you can pour the cold brew into a separate cup and leave the filter inside the bottle to be dealt with later. Neither of those variations is as ideal as removing the filter first, but they do work in a pinch!
Cleaning step: Just detach all 3 pieces (filter, cap and base) and quickly rinse by hand or wash in the dishwasher.