The Gruezi-Bag Biopod is an excellent bag with some unusual features that add a little bulk.

The Gruezi-Bag Biopod is an extremely comfortable bag with a cut that’s a little relaxed. I can lie inside in various natural positions with my elbows out and my knees bent leg bent.

Peter Macfarlane recommends

The features and elaborate design add up to extra bulk which makes this a better winter base camp bag than one I’d carry onto the hill.
Pros
  • comfort
  • performance
  • heat pad
Cons
  • weight
  • pack size
Quick specs
Price: £540
Weight: 1545g
Fill: 700g 90/10, 800+ RDS certified goose down, lavalan AlmWolle wool upper layer
Shell: Recycled, breathable and water-repellent ultra-light 20 denier 380T nylon outer, recycled nylon inner
Construction: V shaped chambers, box chambers, wool overlay, zip baffle, external zipped pocket, adjustable hood and shoulder baffle, powerbank compatible heat pad in foot box
Zip: 2-way full length zip
Length: 215cm
Rating: comfort: -5°C limit: -12°C extreme: -31°C
Sizes: one size
Women/Men’s version: unisex
www.gz-bag.de

The hood is large and warm and can be cinched right in if need be and the hood and baffle adjusters are easy to operate whilst inside. The main zip is a standard type but the main zip puller has a wide plastic attachment which seems to greatly reduce snagging when using the zip.

The down fill lofts well after packing and the bag is nicely warm soon after climbing in. Unusually the top of the bag has a thin layer of wool which to aid moisture transfer, add insulation and prevent condensation that would affect the performance of the down. It’s impossible to see how well this is working inside the construction layers, but the performance is good and the bag doesn’t seem to get as wet-through at the foot and hood as other down bags in a small tent.

Another unusual feature the bag has is a pocket at the left chest where you slip in a power bank that connects to a thin wire that runs down to the foot box where it powers a small heat pad. This adds relatively little weight or bulk and is excellent if need a boost of heat.

There is also an external zip pocket which is handy for a head torch. The underside has anti slip pads and loops for securing to a matt.

The outer fabric DWR is decent for splashes but the fabric does wet out over time against a damp tent inner.

The features and elaborate design add up to extra bulk and weight with a compressed pack size of 33cm x 23cm which, for me, makes this a better winter base camp bag than one I’d carry onto the hills.

Testing notes

Peter used the bags at camp and in bothies from late autumn 2023 to spring 2024 over a variety of conditions and temperatures. The packed sizes were taken from putting each the same compression sack and the weights were taken on digital scales without any stuff sack. You can compare this bag with others Peter tested in our buyer’s guide to the best cold weather sleeping bags.

This review was first published in the January 2025 issue of The Great Outdoors.