Insulated Bottle Bags | For Grayl & Nested 32oz Bottles & Cups

Introducing our handmade bag koozies—the ultimate bottle carriers, designed for use with Grayl Geopress, Grayl Ultra-Press, and standard size 32oz wide-mouth bottles with nesting cups.

In the designing of the bottle bags, we had two main objectives:

To insulate the bottle’s contents, and protect the Grayl’s hollow fiber membrane filters from damage caused by freezing temperatures and expansion.

Another key objective was to ensure sufficient storage space for essential water gear, including a Millbank pre-filter bag, electrolyte tablets, and water purification tablets. We feel we’ve been successful—here’s why:

Maintaining a stable liquid temperature: The bags are lined with high GSM English boiled wool, an excellent insulator, even in damp conditions, boiled wool can absorb up to 30% of its weight in water without feeling damp or losing its insulating properties.

Protecting the Grayl’s Water Filters: Like most hollow fiber membrane filters, the Grayl’s filter is vulnerable to freezing. Expanding ice can rupture the membranes, compromising filtration and allowing contaminants like bacteria and protozoa to pass through. The boiled wool lining helps prevent freezing and protects against potential damage.

Hand-Loops: We know the struggle of removing gloves in the cold! Each size bag has a large handle, allowing you to easily carry and fill bottles without removing the koozie. The loops are also spacious enough to use when wearing gloves. The handles are made from 12oz waxed Cotton canvas, and are double stitched at both ends for added strength.

Waxed Canvas Exterior: The exterior of the bags is made from 12oz cotton, and has been waxed with the Martexin Original Wax blend which produces a superior finish that is virtually water-proof. Martexin Wax is made using a blend of non-hazardous food-grade waxes. The unique formula gives the fabric lifelong resistance to weathering and as it ages, it develops a well-worn patina.

Compatible with 32oz Bottles and Nesting Cups: The nesting size is designed to accommodate the infamous 750ml cup/32oz bottle nesting combination. The top of the bag also provides enough space for an additional cup to be placed on top of the bottle. The drawstring helps cinch down all the components, keeping them secure and preventing any rattling.

The Front Pockets: All bag sizes feature a spacious slide-in exterior pocket, designed to accommodate essential water gear such as a Millbank bag, water purification tablets, and electrolyte tablets. Our goal was to provide ample storage, ensuring all your water essentials can be kept together in one integrated system.

Belt Carrying Loops: We've added two D-rings on the exterior of the bag, allowing it to be easily clipped to your belt, attached to the outside of your pack, or hung up inside your tent or around camp.

What is a Millbank Bag? A Millbank Bag is a water filtration device, designed to remove detritus including sand, mud, silt, and other suspended particulates from water. Even if there is no waterborne diseases present, consuming turbid water can irritate and harm the digestive system.

Why Pair a Millbank Bag with a Water Filter Like the Grayl? While popular water filters like the LifeStraw and Grayl will filter out sediment, doing so significantly reduces their lifespan by forcing more debris through their filtration systems. By using a Millbank bag first, you reduce strain on your filter, extending its lifespan.

**For more details on our Millbank bags, please click here.