Bach Molecule 45 Backpack | Review - Outdoors Magic

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Bach Molecule 45 Backpack | Review

An expansive, well-specced pack that’s light and versatile enough for small to large loads

The Bach brand has been around for over forty years, starting out in Ireland and nowadays, after joining the Scott Sports group, calling Switzerland home. It has tents, sleeping bags and sleeping mats within its repertoire but its probably gained its biggest reputation so far for its backpacks.

Here at Outdoors Magic, we tried out the Bach Daydream a good few years ago and we liked what we saw. This, the Molecule 45, is a newer offering from them – and it’s an equally impressive pack. 

Will with the Bach Molecule 45 on the Welsh coast. Photos: Dave Macfarlane

At 1.1kg, this just about falls within the ultralight category. What you can also do, however, is strip it back to bring it down to just 800g. This is by removing elements including the hipbelt pockets, chest strap, the side straps and the internal frame panel. 

Overall, I’ve found it can hold a lot more than the 45L tag suggests, with the stretchy mesh pockets, floating top lid and daisy chain loops giving a lot of extra load options. The beauty of this pack however, is that the rolltop and side straps also allow you to really minimise the volume, basically turning it into a daypack that’s small enough to use as a carry-on when flying. So the Molecule 45L is essentially a pack that will cater for all trips, big or small. 

Will using the Bach Molecule 45 in the Preseli Hills. Photos: Dave Macfarlane


The main material is a 210D ripstop nylon (made from 100% recycled materials) and there’s a 500D Cordura nylon at the base. Overall, it feels light and tough. In fact, I placed too much confidence in it and managed to create a scuff by flinging the pack onto a rock while it was heavily loaded. While that scuff is still visible on the pack it hasn’t compromised the overall integrity of the bag. 

The water resistance is good and I found the pack kept light rain out reliably. It’s not a waterproof pack though so I’ve always made sure to use this with waterproof drybags.

Fit and Comfort

The back system is fixed and fairly simple. I’ve found it is still comfortable though because the foam padding is thick and located in the right places. The minimalism, for me, is actually quite welcome because it allows the pack to compress completely flat when you want to store it away, whether that’s under your bed or at the bottom of a suitcase when you’re travelling.

I’ve found it handles heavy loads well with the internal frame channelling weight down to the hips well. Fully stripped back, it’s also still a fairly comfortable and functional pack, especially with your gear organised within it to create structure. Even with the frame and back panel removed, you still have a layer of foam to keep things from prodding into you.

I’m 5 foot 10 and tried this in the regular length (45-55cm) and it fitted just fine and the straps allowed for easy refinement while on the go.


One touch I really like is the fact that the rolltop has a zip right at the top of it. It gives that extra bit of security, particularly if you’ve maxed out the capacity so that you can’t really roll the fabric anymore.

There’s a range of pockets, including two deep mesh ones on the side (that are difficult to access without having to remove the pack) and two zipped hipbelt pockets. One of the hipbelt pockets is made from stretch mesh making it perfect for keeping things that you might want to dry out, like a buff or gloves. The other pocket is made from the same nylon used throughout the main body of the pack. This one is big enough for a pack of Jelly Babies or a satellite transponder but it’s not big enough for an OS map unless it’s folded. Both of these pockets are unfortunately a little bit obstructed by the webbing straps – it’s a shame these aren’t located underneath the hipbelt pockets and not over them.

There’s another medium zipped pocket between the shoulder blades which is hard backed so you won’t feel the contents of it against you. Inside the pack there’s a deep bladder sleeve. And last but not least, there’s an excellent stretchy pocket on the harness that has a clever zip that lets you tuck away the mesh fabric when you don’t need it to prevent it getting in the way or snagging. This pocket is big enough to hold a mobile phone, transponder or pair of sunglasses.

One thing I did find was lacking on this pack was a good place to stash a pair of trekking poles. Unless I’ve missed something, the only place you can put them is in the side mesh pockets, which don’t have any reinforcement to prevent the tips from digging in.

The Competition

The Bach Molecule is quite similar to the Hyperlite Mountain Gear Porter 55, although while that pack might be a touch more durable, it also has a much higher price. The Exped Lightning 45 is also quite similar in its design and it sits around the same price point too. That pack is a little simpler in its design, however. If you want a pack with more padding, ventilation and adjustment on the back then the Bach Daydream will likely be a better fit, though that’s not as light as the one on review here.


Tough and functional with some good eco efforts and neat pockets, this is a versatile pack that will suit a range of different trips. I’ve found it to be equally excellent for big treks where I’m carrying all my equipment and for day hikes where I’m carrying a big lunch and lots of layers. I’ve not tried it yet, but I’d even consider using this as a multi-day running pack as its design is quite similar to some fastpacking packs I’ve used.

What I liked: tough, light, useful pocket on the harness, excellent versatility
What I didn’t like: side straps block the hipbelt pockets, not great for stashing trekking poles, back system is fixed.

The pack Will's using here is the smaller Bach Molecule 30.

Bach Molecule 50

Selected for the Outdoor 100 Sping/Summer 2024 guide
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