Coolgear Bru: The All-in-One Cold Brew and Grinder System

The Coolgear Bru is a portable cold brew coffee maker that includes a built-in ceramic burr grinder. It's designed as a travel-friendly, all-in-one system where you grind beans directly into the brewing chamber, add water, and steep for 12 to 24 hours. The concept is appealing: one device replaces both a grinder and a cold brew maker, and the whole thing fits in a backpack.

I got my hands on a Coolgear Bru to test as part of my ongoing search for the perfect travel coffee setup. The idea of combining a grinder and brewer in one package is clever, but ideas and execution don't always match up. Here's what I found after using it for several weeks, including where it impressed me and where it fell short.

What You Get

The Coolgear Bru consists of several components that nest together into a single cylindrical package:

  • Ceramic burr grinder (top section) with adjustable grind settings
  • Brewing chamber (middle section) made of BPA-free plastic
  • Stainless steel mesh filter that separates grounds from the finished cold brew
  • Drinking lid with a flip-top opening
  • Silicone grip band around the center for handling

The assembled unit is about 10 inches tall and roughly the diameter of a standard travel mug. It weighs around 14 ounces empty, which is light enough for travel but heavier than a typical water bottle. The materials feel decent quality for the price point (usually $30 to $45).

The Grinder Section

The built-in grinder uses ceramic burrs, which are common in budget hand grinders. You fill the hopper on top with beans, set your grind size using the adjustment ring, and crank the handle. The ground coffee falls directly through the mesh filter into the brewing chamber below.

Grind Quality

Let me be honest here. The grinder is the weakest part of the Coolgear Bru. The ceramic burrs produce inconsistent particle sizes, with a noticeable amount of both fine powder and oversized chunks in every batch. For cold brew, this matters less than it would for pour-over or espresso, because cold brew is a long immersion method that's forgiving of grind inconsistency.

At a coarse setting (which is what you want for cold brew), I get particles ranging from sea salt size down to fine sand. A dedicated grinder like a Timemore C2 produces much more uniform coarse grounds at the same price point.

Grinding Speed

Expect about 2 to 3 minutes of cranking for a 30-gram dose. The ceramic burrs and small burr diameter mean this grinder is slow. My arm gets tired by the end of a 40-gram dose. If you're making cold brew daily, the grinding process becomes tedious quickly.

The handle is short, which reduces leverage and makes each rotation require more effort. A longer handle would have improved the grinding experience significantly.

The Cold Brew Section

Once you've ground your beans (or added pre-ground coffee, which I honestly recommend for convenience), you add cold water, seal the lid, and put the whole thing in the fridge for 12 to 24 hours.

Brewing Performance

The cold brew itself turns out pretty good. The stainless steel mesh filter does an adequate job of separating grounds from liquid, though you'll notice some fine sediment in the finished brew. This is common with mesh filters and doesn't affect flavor much, but if you prefer crystal-clear cold brew, you'd want to pour through a paper filter after steeping.

I found the best results with:

  • Ratio: 1:8 coffee to water (about 35 grams of coffee to 280ml of water)
  • Grind: Coarse (the coarsest setting on the Bru's grinder)
  • Steep time: 18 to 20 hours in the refrigerator
  • Bean roast: Medium to dark (light roasts can taste thin and sour in cold brew)

The resulting cold brew is smooth, concentrated enough to drink straight or dilute with water or milk, and has that characteristic low-acidity, chocolatey profile that cold brew is known for.

Capacity

The brewing chamber holds about 10 to 12 ounces of liquid, which makes roughly 2 servings of cold brew (accounting for dilution). For a single person, this is fine for a day's worth of cold brew. For a household, you'll need a larger dedicated cold brew maker.

Travel Usefulness

This is where the Coolgear Bru should shine, and it partially delivers.

What Works for Travel

  • All-in-one design. Grinder and brewer in one package means fewer things to pack.
  • Leak-proof. The lid seals well enough that I've carried it in a backpack without spills.
  • No power needed. Everything is manual, so you can make cold brew anywhere.
  • Compact. It takes up about as much space as a water bottle.

What Doesn't Work

  • Brew time. Cold brew takes 12 to 24 hours. This is a "plan ahead" method, not a "I need coffee now" solution. If you arrive at a destination and want cold brew, you're waiting until tomorrow.
  • Grinding is tiring. After a long day of travel, the last thing I want to do is hand-crank a slow grinder for 3 minutes. I ended up bringing pre-ground coffee on longer trips.
  • Small capacity. 10 ounces of cold brew doesn't last long, especially in hot weather when cold brew consumption tends to increase.

For travel cold brew, I've found it more practical to bring a separate cold brew pitcher (or even a mason jar) and a better grinder. The combined device saves a little space but compromises on both grinding and brewing quality.

Alternatives to Consider

If the Coolgear Bru concept appeals to you but you want better performance, here are some options:

Separate Grinder + Cold Brew Maker

  • Grinder: A Timemore C2 or Hario Skerton ($30 to $50) produces dramatically better grinds
  • Cold Brew Maker: A Hario Cold Brew Bottle or Takeya Cold Brew Maker ($15 to $25) brews a larger batch with better filtration
  • Total cost: About the same as the Coolgear Bru, better results, but two devices instead of one

AeroPress for Travel (Hot Coffee)

If you just need good travel coffee and don't specifically need cold brew, an AeroPress with a hand grinder is a more versatile travel setup. You can brew hot or iced coffee in 2 minutes instead of waiting 18 hours.

For more grinder options at every price point, check out our best coffee grinder and top coffee grinder guides.

Maintenance and Cleaning

The Coolgear Bru disassembles into its component parts for cleaning, which is important because coffee oils and residue build up quickly in cold brew makers.

  • After each brew: Rinse all components with warm water. Scrub the mesh filter with a soft brush to remove grounds trapped in the mesh.
  • Weekly: Soak the mesh filter and brewing chamber in a solution of warm water and baking soda for 30 minutes, then rinse thoroughly. This removes oil buildup that can make your cold brew taste rancid.
  • Grinder: Brush out the burr chamber with a dry brush after each use. Don't use water on the grinder section, as the ceramic burrs and adjustment mechanism can trap moisture.

The mesh filter is the component that needs the most attention. Coffee oils accumulate in the mesh over time and eventually affect flavor. Replace the filter every 6 to 12 months if you brew regularly.

FAQ

Is the Coolgear Bru dishwasher safe?

The brewing chamber and lid are dishwasher safe (top rack only). The grinder section is not, and should only be cleaned with a dry brush. The mesh filter can go in the dishwasher but may last longer with hand washing.

Can I make hot coffee with the Coolgear Bru?

The Coolgear Bru is designed specifically for cold brew. You could grind beans with it and brew hot coffee using another method, but the brewing chamber itself isn't designed for hot water. The plastic is BPA-free but rated for cold beverages. Don't pour boiling water into it.

How does the Coolgear Bru compare to the Asobu Cold Brew?

Both are portable cold brew makers, but the Asobu doesn't include a grinder. The Asobu's filtration is slightly better (finer mesh), and it comes in more size options. If you already own a grinder, the Asobu is the better cold brew maker. If you want an all-in-one solution and don't own any coffee equipment, the Coolgear Bru's built-in grinder adds convenience.

What beans work best in the Coolgear Bru?

Medium to dark roast beans produce the smoothest cold brew. Light roasts can taste sour and acidic in cold brew because the cold water doesn't extract the bright, fruity compounds as effectively as hot water. For your first batch, try a medium roast Colombian or Brazilian single-origin. Blends with chocolate and caramel notes also translate well to cold brew.

My Verdict

The Coolgear Bru is a creative product that works better as a concept than in daily practice. The cold brew it produces is decent, but the built-in grinder is underpowered and produces inconsistent results. If you're looking for a portable cold brew solution and don't own any coffee equipment at all, it's a reasonable starting point. But for anyone who already owns a grinder, or who plans to drink cold brew regularly, separate dedicated devices will give you better coffee with less frustration. Buy it for the novelty and convenience. Keep it for the cold brew maker. Plan to outgrow the grinder quickly.