Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Wednesday, February 3, 2016

GEAR REVIEW and My Favorite Gear #9: Sawyer Mini Water Filtration System

In spite of its drawbacks, the 1.3 ounce Sawyer Mini lands on my favorite gear list. It's the lightest and best water filtration system currently available.

By Will Rietveld

Personal water treatment is always a hot topic among lightweight backpackers. We ditched the heavy pump style filters for personal use long ago, but perhaps they still have a role for small groups. Now the personal water treatment debate is about which is the best lightweight effective water treatment system: Aqua-Mira drops, Aqua-Mira tabs, Ultra Violet, or the Sawyer filters. Other “lightweight” filters on the market require expensive replacement cartridges, so I omit them.

Following up on their 2.4-ounce Squeeze Water Filter, Sawyer introduced the Sawyer Mini in September 2013. Weighing just 1.3 ounces stripped, it’s hard to imagine a water filter any lighter than this. However, as you will see, the choice is not that clear cut, each method has its drawbacks.

The new Sawyer Mini water filter weighs just 1.3 ounces (without the cap and drink tube), and can be used a variety of ways. It comes with a heavy-duty syringe (for backflushing), a drink tube (for drinking directly from a stream or lake), and a 16 ounce flask for $24.95.

 Specifications and Features

Sawyer Products (www.sawyer.com)
Sawyer Mini Water Filtration System
Filter, tip cap, drinking straw, cleaning plunger, 16 oz squeeze pouch
Whole kit 4.85 oz, filter without tip cap 1.3 oz, tip cap .05 oz, drink tube 0.2 oz, plunger 1.15 oz, squeeze pouch 0.8 oz


The Sawyer Mini at 1.3 ounces stripped is the lightest water filter currently available. That’s roughly the same weight as using Aqua-Mira drops in small dropper bottles! The beauty of the Mini is it filters to 0.1 micron (the same as the best pump filters) and it doesn’t use expensive replaceable cartridges. It comes with a heavy-duty syringe for backflushing, and it can be backflushed indefinitely; Sawyer guarantees it for 100,000 gallons.

The technology used by Sawyer is adapted from medical dialysis; water is drawn through the side walls of a cluster of micro-tubes into their hollow center and out the end of the tubes. Sediments and organisms are trapped on the outer walls of the tubes. Backflushing (using the included syringe) removes the filtered out debris and the system is ready to use again.

The Mini can be used four ways to filter water: 1) screwed onto any plastic beverage bottle with a standard 28 mm opening; 2) directly from a stream or lake using the included straw, 3) inline in a hydration system, and 4) using the included squeeze pouch to filter water into a bottle for drinking.

The Sawyer Mini does not screw onto a Platypus flask. The Platy threads are different from a common soda bottle, so that’s why Sawyer provides flasks that work with their filters.

Field Testing

I tested the Mini screwed onto a lightweight plastic soda bottle on several backpacking trips. A bottle is easy to fill from a stream or lake and is easy to insert into a side pocket of my pack.

I didn’t use the straw, but I have used the previous Squeeze Water Filter inline in a hydration system, which is a similar concept. I personally did not use method #4 above, but I have observed fellow hikers use that method.

The advantage of using a plastic beverage bottle is that you squeeze the bottle and suck at the same time, which increases the flow rate. Methods #2 and #3 above are suction only. With method #4 above one can roll down the squeeze pouch to put a tremendous amount of pressure on the water within to force it through the filter into another container, then you can gulp it down freely.

My favorite system is the Mini screwed onto a 1-liter beverage bottle. The bottle is free and very lightweight, can be filled from a minimally flowing water source, and is easily inserted/withdrawn into/from a pack side pocket. In contrast, a flask is very difficult to fill from a stream or lake, can’t easily be withdrawn/inserted in a side pocket with the pack on, but it works well for camp water.

Backflushing is essential, and I can’t emphasize that enough. I used both the Sawyer Squeeze Water Filter and Mini on many, many trips over several years and found that backflushing is necessary after every trip; otherwise it is progressively harder to suck/squeeze water through the filter. If you go on an extended trip, take the syringe with you.

Another thing I learned is the filter can become “plugged” if it sits around for an extended period. After using it all summer (and backflushing it after every use, including at the end of the summer), the filter was unused over the winter. On the first trip the next summer it was very difficult to suck or push water through it, which was a pain since I was dependent on it. When I got home I soaked it in water overnight and backflushed it with hot tapwater and was able to restore it to its “normal” performance.

Now for the downside. After using the Mini on several trips, and especially in hot weather, I got tired of sucking hard to get water. I wanted to gulp water down instead of sucking it through a filter; it was too much sucking and not enough drinking. So why not go to method #4 (using the included squeeze pouch to filter water into a bottle for drinking) instead, you ask? That would require an extra bottle to collect the water and pour it into the flask, so extra weight and bulk. It’s hard to fill a flask directly from a minimal water source without stirring up debris.

Another drawback is the Sawyer filtering micro tubes can be damaged by freezing, resulting in an impaired ability to safely filter water. So you can be drinking unsafe water without knowing it. If temperatures are likely to drop below freezing, it’s important to put the filter in a pocket or someplace where it won’t freeze.

Finally, the Mini (or any water filter) is not recommended for turbid water or water with a lot of algae in it. Backpacking in Southern Utah is where I learned that the hard way, and I should have known better. After successfully using the Mini on one trip, where we found clean water, I (and my companions) took it on another trip there where we found only scarce cruddy water. Our filters quickly plugged and were unusable. Fortunately I had some Aqua-Mira tabs along as a backup and that saved the trip.


It seems there is no “perfect” lightweight water treatment method currently available – every method has some drawbacks – so it’s a personal choice based on how one weighs the following factors: effectiveness, weight, convenience, wait time, taste, reliability, and cost.

My personal history with water treatment is probably typical:
  • Aqua-Mira drops are very light weight, but I get tired of the mixing and wait time.
  • Aqua-Mira (and other brands) tabs is the lightest system but they are expensive and you still have the wait time.
  • Iodine tabs are cheap but it tastes bad and you still have the wait time, and iodine doesn’t kill all organisms; chlorine even less so.
  • The Sawyer Squeeze and Mini Water Filters are lightweight and there is no wait time, but I got tired of sucking to get my water, and they clog from cruddy water.
  • The rechargeable SteriPen Freedom (2.65 ounces) is very lightweight, but it’s not recommended for turbid water, and requires a wide-mouth bottle for treatment (see my article on using a zip-lock bag with a Steripen), a full charge may not last through a trip, and electronic devices can fail (which happened to me on one trip).

The “best” water treatment gets down to personal choice, as well as choosing the method that is best for the expected conditions. And carrying some Aqua-Mira tabs as a backup is a darn good idea.


  1. Ah...but there is another solution for the Sawyer system. Use a squeeze bottle, a rock and a pot. Lay the squeeze bottle on a flat rock or tree stump with the sawyer dangling over the edge and a pot below. To speed the process put some rocks on top of the squeeze bottle. Then put the clean water in whatever container you are using for clean water. Voila, you have a gravity system. It is slow - but this is a personal water supply, and I found I got a litre of clean water in about 20-30 minutes. You can finish up with a bit of a squeeze. Yes, you will need one extra bottle for this (marked dirty water!), which adds a few oz. but you still have a very light system, and now no sucking - I never suck!

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