Friday, 19 July 2013

The Sawyer Squeeze Filter System - Initial Review

I have a frequent issue when walking, especially in weather like we are having currently (July 2013 and yes, it's actually hot and sunny). If it's hot, I drink a lot. So I decided that I would like a couple of options for when out walking, as long as there is a known water source whether it be a stream, river, pond or lake. Carrying two to three litres of water, whether in bottles or an hydration bladder is not the best. And if planning a longer trip, such as several nights in Norway as I am, then an alternative is better. And as light as possible can always be an advantage, as long as there aren't too many compromises. So one option I want for is the Sawyer Squeeze. I took it with me on a recent Lake District visit to give it a test.
 
 
Features
 
Firstly, I need to say that I got hold of the SP131 version of the Sawyer Squeeze from the USA. The Sp131 has all three sizes of squeeze bottles, the half litre, one litre and two litre sizes. Sawyer Europe no longer stock this version. They stock SP129, the version with just a single one litre bottle. It is cheaper, but I cannot for the life in me see why they don't stock both.
 
Along with the three bottles I also received the syringe that you use to back wash the filter. The filter is claimed to last for one million litres, enough to last me a lifetime, we shall see.
 
The filter along with a single one litre bag weighs around 85g. My Katadyn Hiker weighs around 300g, won't filter as much water over it's life time, has moving parts which could lead to failure and the Hiker is bulkier. On the other hand, the Sawyer Squeeze shouldn't be as fast. The Hiker filter is 0.3 of a micron, but this is not an absolute figure, so as far as I know, there could be pores larger than 0.3 microns. On the other hand, the Sawyer uses and 0.1 absolute micron hollow fibre membrane filter. This equates to none of the pores being any larger than 0.1 microns. So a much finer filter, which means there should be a much slower flow rate. But the claims of Sawyer are, after watching their video, one litre in around 30 seconds. So there must be a much larger surface area in the Sawyer's filter.
 
In Use
 
In theory, the Sawyer Squeeze should be fairly simple to use as there are no moving parts, just you. It's a straight forward job of filling one of the bags, screw on the filter, and squeeze water into your storage container. But there are a few things to watch for that may not make it quite so easy.
 
I recently took the filter with me on a trip to the Lake District. I had planned a fairly long walk around Derwentwater that I knew would provide a good water supply to test with the filter. I had a break at the south end of the lake next to the River Derwent and filtered water to top up my water bottle and to boil up for a freeze dried lunch.
 
I have seen another review which mentioned that they could not get the bag to fill as it would not expand, probably due to a lack of pressure from the water into the top of the bag. The reviewer used, I believe, an elastic band to hold the bag open etc. All I did was blow a little air into the bag and squeeze the bag along the folds to keep the bag expanded while it filled with water. No issues here as long as you prepare.
 
I screwed the filter onto the bag and turned the whole thing over so the filter was pointing into my bottle. I started to squeeze the bag and got a reasonable rate. Even just holding the bag had a steady, gravity fed flow. But the quickest way I found to filter, with less squeezing was to simply, from the top, to roll the bag up, back to the way it was in the box it came in. This gave a high filter rate, was easier for me than squeezing, and allowed me to take more care with the bag. It may also reduce it's chances of bursting as I felt like I had more control. I was able to fill my one litre bottle in around 30-45 seconds. It may be that the push-pull cap is reducing flow, something I will look at, at a future date.

Conclusion
 
The Sawyer Squeeze certainly ticks most of the boxes. It's quite easy to filter the water, although the two litre bag looks a little daunting for me, which may lead to an alternative methodology for filtering large amounts of water if backpacking.
 
There are a few things I want to try with it filter which I will cover at a later date. One is try a carbon filter inline with the Sawyer as it does not have a carbon insert. I have seen a YouTube video mention that the filter doesn't always remove bad tastes, so a test is to come. The other thing I want to do is test the filter as an inline, closed system, using gravity to flow the water through the filter. This I may do using an unused piece of equipment that may well fit the bill perfectly.
 
Specs from the Sawyer Europe site:
 
All Sawyer filters deliver 0.1 absolute micron biological filtration, removing 7 log (99.99999%) of all bacteria like Salmonella, E. coli, Vibrio cholerae and Salmonella typhi (which cause Cholera and Typhoid); and 6 log (99.9999%) of all protozoa such as Giardia and Cryptosporidium.