Mountainsmith Zerk 40L Backpack Review

If you haven’t been paying close attention to the lightweight backpack revolution, I can now state with confidence that things have really changed. I officially declare that my days of hauling around a five-pound pack to support a load are over! Many of us curiously watched lightweight packs develop from the sidelines but figured they couldn’t handle our load comfortably. How could they? Look at that waistband, you might say! I know, I know…

Enter the Mountainsmith Zerk 40 . It weighs 1 lbs 11 ounces. And it carries gear really well.

Mountainsmith Zerk 40 Test

I tried it out on a recent packraft trip. The plan was this: Paddle six miles, hike out three miles. At the boat launch, I loaded the Zerk inside my boat. This was a real treat because the pack folds in half! It fit inside my boat much easier than my old internal frame pack.

The paddle trip happened, the water was lovely and then it was hike time. Without much thinking, I piled my paddling gear into the pack. I started with the rolled up boat and then added all the odds and ends. I know the pack is well-thought out because I really did not have to strategize or pack well. The Zerk gobbled up my paddling gear, which doesn’t consist of the most standard shapes. Everything seemed to have a place including the extra shoes I brought (wet shoes went in the stretchy outside pocket). The flexible foam pad in the back helped the pack keep shape and ensured I wasn’t stabbed by sharper gear put in the wrong spot.

Mountainsmith Zerk 40 Size

I filled the 40L backpack to the brim, did a couple folds like a drybag, then clipped the buckles on the ends to a strap on either side. It was easy and secure. My  water bottle was easy to stash and access in the side pocket despite the paddle being there. There are actually two pockets on each side with stretchy elastic to help store multiple gear pieces.

I LOVED the sternum pockets. I placed an energy bar in there as I knew I was getting a little hungry. There was also room for my sunscreen in another pocket so I could be sure to reapply. There is even a phone pocket with a cinch down cord. It worked great. I consulted the map on my phone a couple of times and took a couple photos on the hike out with ease. The shoulder straps and these pockets remind me of a running vest. They are very secure yet spacious. They really make the pack fit well.

Now for that waist belt. I was surprised to see that it is just webbing. It didn’t feel bad. Would I like just a little bit more in this area? Maybe. But, the aforementioned shoulder straps are really what make the pack fit while still directing weight to the waist.  The Zerk was very comfortable with ~ 17 pounds of gear on the hike out.

Mountainsmith Zerk 40L Backpack Pros & Cons

Pros:

• Weighs only 1 lbs, 11 ounces
• Carries gear comfortably and securely
• Smart design and sufficient size

Cons:

• Webbing waist belts may lack support.
• May not be suitable for heavy loads.

Overall Impression

If you’ve been waiting for the perfect lightweight pack to try out, I wouldn’t hesitate to recommend the Mountainsmith Zerk 40 Backpack ($219.95). Its smart design, light weight and sufficient size make it a very versatile companion. I look forward to trying it out with standard backpacking gear. If it can handling paddling gear, I feel that it can handle most anything!

Related Packrafting Gear

1. Six Moon Designs Flex PR Packrafting Backpack
2. Sea to Summit Hydraulic Dry Bag
3. Alpacka Expedition Packraft