FAQs, Tips, Tricks & Bizarre Stuff

Sure can! Here's a link to a copy of those simple instructions we included on the hangtag of your Rumble Jar. Feel free to print it out a thousand times to make some avant garde wallpaper.

Whoa, take it easy over there! Quite frankly, you can do whatever you like, but we wouldn't recommend over-shaking. Actually, don't shake it at all. In general, the "Rumbling" step (i.e. agitation) is just intended to soak all the grounds in water. Over-agitating definitely won't make better coffee, but it definitely will make more silt/sediment! 

If you're brewing with the barista-recommended coarse grounds, just rotating the jar 90 degrees until it's horizontal a couple times should be plenty. To watch proper rumbling in action, have a look at "Step 2: Get your rumble on" in our Brewing Instructions page

And if you're using fine grounds, don't worry...we won't rat you out to a barista. But you may want to add a couple more rumbles if you're noticing the dry grounds issue (see related FAQ).

We've seen this happen a few times with certain well-known and very-affordable brands of pre-ground coffee. After brewing, you might notice some of the grounds in the center of the filter still appear dry. Well, that's because they are in fact still dry! If you use the kinds of beans mentioned above and notice this happening to you, here are a few fixes for your next batch (try them individually, in this order):

1) Fill up water level so it covers the cap. Coffee grounds float, so this ensures the grounds will remain under water while they're brewing. 

2) Use a total of 4 "rumbles" rather than the recommended 2 rumbles ("rumbles" are the standard end-over-end horizontal rotations depicted in step 2 of our instructions).

3) If those 2 additional rumbles still didn't do the trick to soak all the grounds, try giving it two horizontal shakes on your next batch (i.e. hold the jar vertical, but shake the jar horizontally). This loosens up the grounds that might be caked onto the wall of the filter and plugging up the holes, preventing water from circulating. Don't overdo this step though...too much of it can create a lot of sediment.

4) Consider using coarse grounds. They're recommended by the cold brew experts anyway, and we almost never see this dry grounds issue occur when brewing with coarse ones.

If you're steeping in a refrigerator: 16-24 hours. 
If you're steeping at room temperature: 8-12 hours.

While not strictly necessary, coarse-ground coffee is far preferred to finer-ground coffee for two reasons: 1) coarse grounds result in far fewer particles (aka "silt" or "sediment") winding up in the drinkable brew, and 2) finer grounds have a tendency to "over-extract" (a fancy term describing a brew that's overly bitter and pungent). If you're familiar with the ground size typically used in a French Press, Chemex, dripper or percolator, you can basically just use that same size. Trust us...you really can taste the difference, so it's worth doing.

You can still make cold brew just fine if you're using fine grounds in your Rumble Jar though. If you're OK with a little more silt in the bottom of the jar or a bit more tangy flavor, it still works well. Plus, Rumble Jars do come nestled in a 100% cotton bag that doubles as an optional second-stage filter for folks sensitive to the silt left over from the finer grounds. The second-stage filter does a phenomenal job at filtering out the excess particles, but it's an added step that could be a bit overkill for the average person and totally unnecessary if you use coarse grounds.

Rumble Jar

By weight (quart size / half gallon size respectively)

Filled to the Lower Notch: ~1.5 ounces of ground coffee (quart size) / ~3 ounces (half gallon size)
Filled to the Upper Notch: ~3 ounces / ~5 ounces
Maximum: ~4 ounces / ~7 ounces 

By volume (quart size / half gallon size respectively)

Filled to the Lower Notch: ~half cup (~120 mL)* / ~1 cup (~240 mL)*
Filled to the Upper Notch: ~1 cup (~240 mL)* / ~ 1.5 cups (~360 mL)*
Maximum: roughly ~1.3 cups (~320 mL)* / ~2.3 cups (~560 mL)*

Rumble Go

By weight (fully-collapsed / fully-extended respectively)

Filled to the Lower Notch: ~0.75 ounces of ground coffee (fully collapsed) / ~1.5 ounces (fully extended)
Filled to the Middle Notch: ~1.5 ounces / ~2.25 ounces 
Filled to the Upper Notch: ~2.25 ounces / ~3 ounces
Maximum: ~2.5 ounces / ~3.25 ounces 

By volume (fully-collapsed / fully-extended respectively)

Filled to the Lower Notch: ~quarter cup (~60 mL)* / ~half cup (~120 mL)*
Filled to the Middle Notch: ~half cup (~120 mL)* / ~three-quarter cup (~180mL)*
Filled to the Upper Notch: ~three-quarter cup (~180mL)* / ~1 cup (~240 mL)*
Maximum: ~0.8 cup (~190mL)* / ~1.1 cups (~260mL)*

*For more on the insanity of using "cup" as a measurement tool, have a look at our Bizarre stuff section below.

We made that mistake once before! Since grounds expand when they get wet, an overfilled filter can end up popping the cap off your filter while your coffee's brewing and leak grounds into the drinkable brew. So try not to fill too far above the highest notch, or you might have a gritty start to your day!

Our only recommendation is to use coffee that's coarsely ground instead of finely ground. Other than that, it's entirely up to you which type of coffee (roast or bean) you use in cold brew. If you're new to cold brew, we recommend experimenting with a few different roasts or flavors though, because cold brew tastes quite a bit different than your typical hot coffee, so you might find your taste preferences change a bit. We've heard reports of folks discovering a preference for darker roasts for their cold brew, since that adds a bit more strength to counteract cold brew's sweeter flavor and lack of acidity.

"It depends" is a lame answer, but it definitely does apply here. Being prescriptive about the correct coffee-to-water ratio is impossible (and anyone telling you they know the answer is just making it up!). It's highly dependent on your ingredients (beans, how they're ground, roasting method, etc.), the brew method (time, fridge vs room temp, type of water, etc.) and most importantly your individual taste preference. So if you Google it, you'll see an incredibly wide array of opinions about the correct ratio. 

So our best advice is to use your Rumble Jar or Rumble Go to figure it out yourself. We've included those notches (i.e. short horizontal lines) on the side of the the metal filter as guides, not as prescriptive tools. They're there to help you eyeball your grounds as you prepare a batch and roughly figure out how much you personally prefer. We've found that the vast majority of cold brew drinkers prefer to fill up the filter with grounds somewhere in between the lower and upper notches. 

Rumble Jar: The lower notch is our best guess for where you'll want to start (~1.5 ounces of ground coffee in the quart size and ~3 ounces in the half gallon size). Fill your grounds to that line, drink a batch of cold brew and then reassess to figure out whether you want more grounds for your next batch. The higher notch holds ~3 ounces of grounds in the quart size and ~5 ounces in the half gallon size. Some folks like to brew a higher-strength "concentrate" and then dilute it with water/milk/ice when they drink it, so that's an option too if you want to get more cups out of a single batch of cold brew.

Rumble Go: Given the height-adjustability of the base, the capacity of the filter changes depending on how tall you make your filter. In general, we've found folks brewing in 16-24oz bottles fill the filter with grounds between the lower and middle notch. Folks brewing in 25-32oz bottles fill the filter between the middle and upper notch.

We recommend filling your jar or bottle to the very top with water (i.e. make sure the water line is above the silicone cap). This ensures all the grounds will remain below the water line during the steeping process, which will make sure all the goodness is soaked out of them overnight.

If you want to vary the strength of your brew, it's best to do so by adjusting the amount of grounds you use in the filter.

Cold brew can be stored up to two weeks in your fridge (as long as the grounds have been removed), so long as it's stored in an airtight container. That's because oxygen is known as the "coffee killer"! A big reason we designed our original filter to work in tandem with the the Mason jar was because their airtight seals are some of the best on the market. They'll keep your coffee fresh for a while. 

So don't worry about brewing too much coffee. You can always store the rest for later in the week. Just make sure those grounds don't steep for longer than 48 hours, or else it could taste a little funky.

We think cold brew is the ideal way to make coffee when you're outside your home, so we built Rumble Go to meet that need. Outside Magazine explained it really well in their write-up about Rumble Go: "In the morning, your cold-brew coffee is ready to drink the moment you get out of bed or your sleeping bag, so you don’t have to fumble around to boil water." 

Read more in this article about why cold brew is the best way to make coffee outside your home.

We intentionally designed our Rumble Jar filters to work with Mason jars because 1) they're the best drinking/brewing/storage vessels ever made, 2) they have a truly airtight seal that prevents oxidation from happening (oxygen is the coffee killer!), and 3) they're easy and inexpensive to replace in case you lose or break it. Affordable and high quality is a combo we love! 

The Mason jars that are compatible with our Rumble Jar filters are among the most widely available versions you can find (and they're also very affordable!). 

Quart-size (32oz) Rumble Jars

The complete 32oz Rumble Jar brewing kits already come packaged with the compatible wide-mouth Mason jar. In case you're buying the standalone 32oz Rumble Jar filter or you need a replacement Mason jar, the key things to look for are WIDE MOUTH (i.e. not regular mouth) and STANDARD (i.e. not the more obscure ones with odd sizes or fancy shapes). 

Half-Gallon Rumble Jars (filter-only)

Our half-gallon (64oz) Rumble Jar filters don't include a Mason jar. In addition to these jars being super expensive to ship individually, tons of folks have told us they already have one at home they can use. You can usually buy a dozen in a store for about the same cost as buying just one online (so chalk up a win for brick-and-mortar!). That's the reason we go strictly filter-only for this half-gallon size. The other really nice thing about the half-gallon size is that there is really just one standard mouth size, so you don't have to worry about the wide-mouth vs. regular-mouth distinction like you do with the quart-size jars. With half-gallon jars, they're basically all in wide-mouth form (except for a rogue "Extra Wide Mouth" decorative jar that we're fairly confident you don't own and wouldn't be tempted to use for coffee anyway).

As always, feel free to send us an email in case you have a question about a particular Mason jar model, and we'll be happy to steer you in the right direction. 

In short, we do! All Rumble Go filters are only available as a standalone filter because they're built with a universal design that should work with a wide-mouth bottle you already own. As for the Rumble Jar, the half-gallon size is only available as a standalone filter, and that's because those half-gallon Mason jars cost a fortune to ship. Plus, unlike the quart size jars which commonly come in two different mouth sizes (regular mouth and wide mouth), the half-gallon version only comes in a single wide-mouth size. So there's basically no comptability risk there. The quart-size 32oz Rumble Jar comes in both a complete kit form (which includes the compatible Mason jar) or in standalone filter form. If you're buying the latter, just make sure you've got a wide-mouth quart size jar at home (it won't fit in the regular mouth version!) 

Rumble Jar filter (quart size)

Diameter of metal filter: 2.5"
Diameter with silicone cap attached: 3"
Height of metal filter (cap-less): 5.5"
Height with silicone cap attached: 6.25"

Rumble Jar filter (half gallon size)

Diameter of metal filter: 2.5"
Diameter with silicone cap attached: 3"
Height of metal filter (cap-less): 8" 
Height with silicone cap attached: 8.75"

Rumble Go filter

Diameter of metal filter: 1.9"
Diameter with silicone cap & base attached: 2"
Height of metal filter (cap-less): 5.4" 
Minimum height with cap & base attached: 6.25"
Maximum height with cap & base attached: 7.75"

For more about Rumble Go measurements, see this reference page: Rumble Go compatibility.

Yes.

When you receive your Rumble Jar, you'll find it nestled comfortably inside of a 100% cotton filter-bag. Hang onto that bag! It functions as a pretty fantastic (and totally-optional) "second-stage" filter.

How do I use the filter-bag? It's really only useful if you're forced to make cold brew with fine grounds (remember: coarse grounds are recommended for making cold brew). Once you've brewed a batch of cold brew with fine grounds and removed the filter+cap from your Rumble Jar, you can add an optional step where you use the filter-bag to strain your batch of cold brew a second time to remove additional silt/sediment and produce a clearer-looking brew. Have a look at our FAQ about using coarse grounds and our FAQ about silt for more on that topic.

Isn't this extra filtering step time-consuming and anti-Rumble Jar simplicity? Perhaps...and that's why it's completely optional and only suggested for folks brewing with fine grounds. This extra filter may be helpful if you only have finely-ground coffee available, since that tends to produce more silt/sediment than the coarse grounds recommended for cold brew. 

Personally, we don't use the second-stage filter because we brew with the recommended coarse grounds, and we've grown accustomed to a little bit of sediment that's characteristic of cold brew. But if you use finer grounds and want a surefire way to get rid of extra sediment, give that secondary filter a go! And if you have no need for a second-stage filter, you can always repurpose it as a bag for like, storing stuff.

How do I clean the filter-bag?  Have a look at our cleaning instructions section.

Most filters have holes in the bottom that match the holes in their walls. Instead, we designed the bottom of the Rumble Jar and Rumble Go filters to feature a hole-free dish that we call a "silt pan" (have a look at the close-up photo here). When you're removing the filter from the jar, that silt pan collects some of the excess sediment and prevents it from draining into your drinkable brew. If there were holes in the bottom, that sediment would immediately drain out into your coffee. Our silt pan certainly doesn't capture all of the silt/sediment, but we were definitely able to notice a difference.

Sure can! Just shoot us a note via our Contact page (or scroll to the bottom of this page for a Contact link) and please include your order number to get started.

Rumble Jar and Rumble Go are:

• Designed in USA. 
  
• The Mason jar (included with quart-size Rumble Jars only) is made in USA. 
  
• The metal filter and silicone caps/bases are made in Taiwan or China. 
  
• The cotton secondary filter-bag (included with Rumble Jars only) is made in China. 

Yes. You can clean all components (excluding the cotton bag) in a dishwasher or by hand.

First, we typically dump out as many grouds as possible into the trash/compost (side note: try this gardening trick!). A couple quick upside-down vertical shakes and that's that. Then we typically rinse the grounds off the walls of the filter by running the faucet along the outer walls of the filter. Then, we run the faucet inside the filter, and what you'll notice is that a pool of water will collect in the bottom before it quickly drains out through the walls. So we basically take advantage of this temporary pooling effect by doing a series of rapid fill-and-swirl-then-dump-upside-down maneuvers one after the other. We personally don't mind a couple stray grounds left in our filter, but if you do enough of these maneuvers, you can definitely get all of them out! 

Rinsing thoroughly with water and air-drying is probably the most used option, but for a more thorough clean you would put them in a washing machine (but air dry or else they'll shrink and get warped). We don't recommend putting them in a dishwasher, but that's also an option. Anyway, cleaning these things properly can be a bit of a chore, which is another reason we don't love using them!

Air! Well, technically it's really just the oxygen component that does the most damage to coffee (side note: carbon dioxide is actually somewhat protective in fact). And oxygen isn't just cold brew's enemy, but more generally it's coffee's biggest enemy in all its various forms (beans, grounds, or ready-to-drink). The reason why it's especially destructive with cold brew is that cold brew is often brewed in a batch and stored for days. But if you're not storing it in an airtight container, it will quickly oxidize and get nasty. So you need to keep oxygen out of the picture. This is a big reason we built our original Rumble Jar filter to work inside a Mason jar. As you probably know, Mason jar's have a ridiculously good airtight seal. Without a seal like that (or in any container with a so-so seal), your cold brew will be oxidizing while it's stored in your fridge.

Pro-tip: use a spare Mason jar to store your whole beans before you grind them, and just store it in a pantry away from sunlight. That will keep your beans as fresh as just about any other specialized storage solution we've come across.   

A lot of folks find it just plain-old tastes better. The secret is that cold water extracts ~70% less acid from the coffee grounds than hot water (plus it also pulls out fewer alkaline solubles), which means that your coffee ends up tasting a lot less sour and bitter. So if you're new to cold brew, get ready to enjoy a smoother, sweeter flavor of coffee.

Nope. Iced coffee generally refers to a standard drip hot brew which is then poured over ice to cool it down. Since the coffee is originally brewed with hot water instead of cold, it's more acidic and tends to have a stronger, more bitter and more sour taste.

This is a tough one to answer because it really does depend on your variables, but in practice, ready-to-drink cold brew typically contains a very similar amount of caffeine to hot-brewed coffee. There's a misconception out there that cold brew contains a lot more caffeine, but folks are generally referring to cold brew concentrate before it's been diluted. 

Here are a couple articles that do a good job getting to the bottom of this question:

https://www.cnet.com/how-to/coffee-vs-cold-brew-vs-espresso-which-has-the-most-caffeine/

https://www.huffpost.com/entry/cold-brew-caffeine-content_n_593eab44e4b0c5a35ca17350

Only the good stuff! Unfortunately if you removed all silt (aka "sediment") from cold brew coffee, you wouldn't have all that much coffee left over...and what you did have left over wouldn't taste all that good! The silt is caused by tiny coffee particles sneaking through the holes in the filter. These particles are also found in traditional hot-brewed coffee, but you just don't notice them as much because the heat disperses the particles throughout the cup. They're still there, but you just end up drinking them. Cold brew's long-steeping process results in this silt sinking to the bottom. We've been warned by our cold brew expert advisors at Jittery John's that silt is a natural feature of cold brew coffee, and if you eliminated all of it, you wouldn't like the result!

If you're used to drinking hot coffee (and particularly if you prefer strong, dark roasts), there's no question cold brew will taste different. It should taste lighter, sweeter and more balanced, but it should not taste watery. If you're finding it tastes watery, the best solutions are to increase your steeping time to a full 24 hours, ensure all grounds in the filter are initially soaked (via "Rumbling"), and potentially use a darker roast of coffee. Regardless, it will be impossible to replicate the more bitter and acidic taste of traditional coffee, so if that's what you're craving, hot coffee might be right for you.

We have no idea.  

The general consensus seems to be that the freezer is a bad place to store beans/grounds, the fridge isn't great either (because it's too humid), so your cupboard is probably best since it's dark and coolish and usually not too humid. Since your biggest concern should be exposure to air (since oxygen is coffee's #1 enemy), we actually turn to our trusty Mason jar to store beans and grounds, since we know a Mason jar's seal is as airtight as they come. But some folks actually say keeping it in the bag is best, while others recommend vacuum canisters like this one by our friends at Fellow.

Unless noted otherwise, we use USPS for all shipments, domestic and international.

We typically ship out orders same-day or by the next business day.

Domestic: For the vast majority of the US, shipping will take 1-3 business days from when it's shipped until it's delivered to you. More remote US locations might see this timing stretched to 3-4 business days. 

International: We send packages via USPS' Priority International service, and they quote 6-10 business days for delivery. Keep in mind that customs delays can happen and also that the package will be handed off to your local mail carrier for final delivery, so those issues can occasionally extend the timing beyond 10 days. In our experience though, Priority International has done a great job of delivering the vast majority of customers' packages quicker than 10 business days.

Because so many folks from abroad were awesome about asking us for our filters, we now offer international shipping to a whole host of countries. If shipping isn't available to your country, please send us a message and we will look into the policies and costs and let you know if we can add it. 

IMPORTANT: Our international shipping costs do not include customs fees or taxes. Sorry about that! So, just make sure you take into account any additional fees and taxes charged by customs in your country, as well as for ensuring the imported product complies with your local laws. Thanks for your understanding!

Of course! Cold brew makes for an excellent iced coffee, and it's super easy to make with a Rumble Jar or Rumble Go. Just brew a batch normally, but make sure to use more grounds in the filter than you normally would. Consider filling up the filter to the highest notch. The reason is that once you pour your fresh-brewed coffee over ice, the ice starts to melt and dilute your coffee, so starting with a a stronger concentrate will counteract any watery taste.

Nope. Iced coffee generally refers to a standard drip hot brew which is then poured over ice to cool it down. Since the coffee is originally brewed with hot water instead of cold, it's more acidic and tends to have a more bitter taste.

There's good news for you, but you'll have to enter our Secrets & Tricks portal to learn about this secret/trick.  

This cold brew horchata recipe is delicious, but we tried it with cold brew instead of iced coffee and it's even better. Give it a shot!: https://food52.com/blog/22218-brown-rice-horchata-for-iced-coffee

(and for the difference between cold brew and iced coffee, please see this FAQ)

We've been in touch with a next-level customer who was making sous-vide brew coffee. Yes, that's right, sous-vide brew! As if we didn't already love how creative Rumblers get with their coffee, someone had to go ahead and make sous-vide brew to top it off! Love it! 

And guess what? It apparently turned out really well (and the sous-vide heating process obviously accelerates the brewing process so it only takes a couple hours instead of overnight). We tried it too and it really does work. The taste lands somewhere in between a typical hot brew and cold brew, as one might expect. Could this be the next big thing in coffee??? Please give it a shot if you have a sous-vide setup at home!

We got this "best coffee ever" recipe in the Kickstarter comments section from a backer of the original Rumble Jar, so we thought we'd reproduce it here, word-for-word. I mean, it's the "best coffee ever" after all, so at least worth a shot, right???

Aaaand here's where I am at now. I got my hands on some really nice medium-to-dark roast from Brazil, and another from El Salvador.
- 50g coarse grounds (14 clicks on my hario slim) consistently gets me up to between the first and second marking
- plop the filter sleeve in, add in filtered water to the brim (I use a simple Brita filter. Filtered water makes a huuuge difference esp if you live in the city where the water is chlorinated. You'd be surprised at how much chlorine warps the aroma of coffee)
- I rumble the jar once, then let it sit with the lid off for a minute. During this time, the grounds really soak in the water, and I'll commonly see the water level drop about a quarter to half inch. I top it up with more filtered water
- let it sit 12 - 16 hours at room temperature
- after removing the filter, I let the whole jar sit in the fridge for a few hours to let all the silt settle
- tuck into the best coffee ever

Like iced coffee but hate when it gets watered down? Instead of using normal ice cubes that will end up melting and diluting your cold brew, take some of your cold brew, pour it into the ice tray to make cold brew cubes, and voila you've got magical ice cubes that will never water down your iced coffee!

Here's another recipe we received from a backer's comment to our original Rumble Jar Kickstarter campaign:

I have to say this is one of the best things I've ever backed on KS. I have a routine going where I make the coffee in the evening per instruction, stick it in the fridge overnight. I get another jar in the morning, stick the cloth sleeve in, then filter the coffee. I then throw about a tablespoon of condensed milk in the jar and whisk it will incorporated. Split the content with yet another jar, give one to the hubs and take one with me on the commute to work. In the evening I scrap the dried up grounds into my compost and plop everything into the dishwasher with the rest of the dishes. Since I got a 3 pack (gave one to my mom), I'm able to pipeline the process every day. It's been saving me a sbx trip (and $5) on a daily basis. Great stuff :)

You can indeed make cold brew and then heat it up. It won't suddenly turn bitter and lose its sweeter flavor. That's because the acidic compounds reside in the coffee grounds, so once they're removed (and please don't forget to remove those grounds before heating!), you can prepare your coffee any way you like. So go heat it up on the stove or in the microwave (just make sure to keep it below a simmer!) and then add whatever else you normally would to your hot coffee. But our bet is you'll find yourself needing less sweetener than you did before. 

This pro-tip came courtesy of a Kickstarter backer and we've been able to reproduce it as well (but only on the quart-size Rumble Jar): When you're pulling out the filter, you can perch the base of the filter at an angle so it's perfectly balanced on top of the rim of the jar, and it's an impressive-looking and also practical way to ensure all the final drops make it into your drinkable brew so you don't waste a single drop.

That cotton filter bag is a totally-optional second stage filter for your Rumble Jar. And while only maybe 5% of our customers end up using them, those that do may want to give this method a shot to make it the straining process a whole lot easier. You basically tighten the bag using just the outer screw-on band from the Mason jar's lid, and then just pour into a new container. We'll let the pic do the talking, which came along with this pro-tip from one of our most creative Kickstarter backers.

The cup is an official measurement of insanity. For more on why, we turn to this HuffPo article or this Wiki article about all the varying definitions of one cup. And going forward let's never refer to a "cup" as a measurement again.

Although masonry professionals are tehcnically still allowed to use them, Mason jars actually get their name from their 19th century inventor, a fellow named John Landis Mason. More about him and the riveting history of Mason jars can be found on this Wikipedia page. You might need a full Rumble Jar in order to read the article in its entirety.