The Science of Water

  • Hey Guest, For sale we have Hultafors Outdoor Knives with Firesteel PLEASE LOOK HERE for more information or use the Pay Now button in the sidebar


Jul 31, 2012
Really interesting debate and very informative OP

Just to add a bit in to the debate on altitude and sterilization (I don't know a huge amount about this but have a little knowledge as I started out many moons ago working as an industrial microbiologist).

Killing bacteria with low temperatures is not effective, for most bacterial groups its not the temperature but how they get there that causes them problems. We used to have a "culture store" for isolated strains of bacteria, this consisted of a giant freezer at -74degC. Routinely we would store bacteria for up to 2-3years in this then successfully re-culture them. This is because rapid freezing prevents the formation of the ice crystals that puncture the bacterial cell and kill it. So be careful as cold may only mean dormant bacteria which when warmed will begin to metabolise.

In terms of heating to sterilize at altitude this is effective against bacteria even at 70degC as if the water in your pot is boiling so is the water in the bacterial cell rupturing and disrupting it. Caveat - for most common types of waterborne bacteria there are many that can survive this, thermophilic types if my memory serves me correctly can survive up to 122 degC. This is one of the reasons industrial labs use high pressure autoclaves. Bacteria themselves once water is boiled aren't such a problem (as someone else posted) at lower temps the problems can be the toxins they may leave behind as these might not be de-natured with short boiling times.
Virus's another storey all together...
A one of the things you can do is always boil a pot with the lid on... this will increase the temperature within the pot and the pressure slightly (also holding in steam which is a fantastic sterilizing agent as it kill micro-organisms by giving up its energy quicker than the cell can absorb). I read in a book some time back about a tribe somewhere or other that actually seal the lids of their boiling pots with clay to increase the pressure and when the lid blows off the water is done (not sure how safe this is :confused: ).

Its been a long time since I have done anything to do with this so I may be mistaken... either way though its made my brain hurt...
I was told but cannot confirm that if the water is full of chemical contaminants you redo the steps 1-2-3-4 and 6 again.

Basic filtering and boiling will have no effect on chemical contaminants. In fact, boiling will only serve to concentrate the chemicals as you're reducing the volume due to escaping steam. The only way to get rid of chemicals is to get the water out by distillation.

British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
The word "science" was included to disabuse you of thinking this contained anything homeopathy related ;)

Sorry to disappoint with a science and fact based thread :D


Silver Trader
Jun 8, 2011
I just thought I'd bring peoples attention to this newly released bit of kit.

I have no links with Sawyer blah blah blah but I do have several of their filters which I'm happy with. They do relatively cheap filters with astounding capacities which remove bacteria etc. They also do pricier ones that remove viruses but that isn't really an issue in Northern Europe. This is a very adaptable bit of kit that uses kidney dialysis technology. It can be used for inline, gravity feed, pressure feed, direct from a water bottle, as a straw etc.

I have the SP129 and the Sp191. Looks like I'm going to have to acquire an SP128 too.

I thought I might do a group buy in May coming up to the Moot.
Last edited:


Oct 2, 2004
An interesting point from BrettaBoy, but I'm curious why the site needed to send me 14 emails to tell me he'd made it!


New Member
May 26, 2015
Didn't see it mentioned anywhere, you should always check pH values of drinking water. Water shouldn't be too high in acidity or low in alkalinity as they will will make you damn sick. Low alkaline water will make you throw up like in the Exorcist.

British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
The technologies haven't changed much, but pressure filtration across a membrane is now affordable and portable ( reverse osmosis). I did a version of the article to include this, I Wii post it here when I have a moment. Worth noting that iodine is now regulated for water purification.


Bushcrafter through and through
Jul 6, 2011
East Sussex, UK
Looking for a system to use at home for providing drinking water to the family from the well in case of emergency. Needs to be able to be stored for a long time & shouldn't need power

British Red

M.A.B (Mad About Bushcraft)
Dec 30, 2005
One of the large stainless gravity filters should do it - that what we use. Freshwaterfilter or British Berkfeld
Mar 26, 2018
Great thread and advice thanks. I am a regular walker in Scotland and I'm pretty spoilt for clean water in the hills (obviously). There is always a risk of something dead upstream though so I have considered different solutions and have settled to using a Travel Tap by Drinksafe systems. The travel tap is a water bottle with a filter inside that claims to filter pretty much everything nasty you can think of! I have been using it for a couple of years now and have used it to drink really peaty water in the flow country (there was a frog watching me underwater as I scooped it up) with no ill effects. For travelling light, I find this very handy as the water bottle is all you have to carry and it filters as you drink. The bottle lid was a bit leaky to start with and the seal kept falling out to start with too, but with use, this has bedded in.
I must add that I'm not affiliated in any way with them, I'm just a user of their water bottle.


Full Member
Mar 25, 2017
I've really enjoyed reading this thread today but was surprised that (as far as I could see) no-one has pointed out the fairly obvious, but oh so easy to forget: you need to keep track of your "untreated" and "clean" water containers.

No point in spending all that time and effort cleaning water if you then reintroduce bacteria etc by getting the two types of water mixed up.
This is my main issue with filters built into drinking bottles and systems thst requires a cup or something to fill them up.

Hultafors Outdoor knife for Sale

We have a a number of Hultafors Outdoor Knives with Firesteels

You can see more details here in this thread OUTDOOR KNIVES

The price is £27 and you can pay via the paypal button below.