Personally, I prefer Platypus Big Zip hydration reservoirs.
This post is written to dispel myths which are commonly used to try and claim that reservoirs are either less sanitary to use, or are less easy to use than bottles.
I'm
NOT writing this post to suggest that I and others who prefer reservoirs are making the best and most superior choice; I am doing this to preempt those who misstate facts to claim that using hydration reservoirs is the WRONG way to go.
1.
Sanitation. Bottles have no advantage. Reservoirs stay as sanitary. They do not require cleaning every day, nor do they need to be dried.
As with plumbing, it is the change of water and water flow through use that keeps things fresh. With normal use, both bladders and bottles are constantly refilled and emptied That keeps them sanitary UNLESS contaminated water is introduced, or other fluids with sugars (juices, energy drinks, soda pop, etc) are put into either storage container.
While working for the local public health district, I did a review of the literature, which I again did in 2016. Comparisons of bacterial contamination levels between bottles and hydration bladders were indistinguishable -- both had equally low rates of bacterial contamination. And both were at about equal risk for developing significant levels of bacteria and mold if not cleaned and dried properly prior to storage. In the last few years, the hydration reservoirs have become more modular in nature and have wider openings to access the water compartments, making it much easier to clean and prepare for storage than previous generations of the product.
One study, from 2009:
https://www.wemjournal.org/article/S1080-6032(09)70419-3/fulltext
When it is time to store bottles or bladders away for the season, they can be sanitized if desired with a bit of bleach added to the final rinse water during cleaning. It is not necessary, but there is no harm in doing so. Then they can be rinsed out and be allowed to dry.
Molds and other nasty things occur if either container is stored
with water over a period of time, or have contained other fluids which might have sugars and not properly washed out prior to long term storage..
2.
Ease of Use. I find it personally easier to raise the mouth tube on my shoulder strap to drink from. I do not like to reach around to a side pocket, or even need to take off my pack to do so. I definitely do NOT like stuff hanging on my shoulder straps like bottles of water.
Again, this is personal preference, not an issue of something being 'better'. Access water bottles is not an issue of usability for bottle users.
3.
Weight. Here is where two major claims are made, one is correct and the other is not.
A typical empty 2 liter reservoir weighs around 4 ounces. The equivalent in bottles around 1.5 to 3 ounces. Depending on bottle material used, though, bottles can weigh up to 8 ounces.
So while it is correct that bottles can weigh less, it is not a significant issue of consideration with overall backpack weight.
The other issue is capacity and weight.
No, one does not have to fill a reservoir to the tippy top. I will carry as much water as I
need to carry from water source to water source. So regardless of container used, water weight is related to the individual's decision about how much to carry, and NOT on a container's capacity.
4.
Refills. This is actually a subheading under 'ease of use', but it is frequently pointed to as why bottles are better than reservoirs.
I can refill my reservoir without even removing my backpack. One does
not need to pull a reservoir out of the pack. It is a matter of using a quick disconnect system which is a simple and cheap add on accessory.
For those interested in adding a quick disconnect adapter to your hydration reservoir/bladder, I've added a link below. With the quick disconnect added, I don't even need to remove my pack to do a quick and easy refill of the bladder.
The video shows the quick disconnect being used with a water filter as it might be used for wilderness backpacking. It is the way I have it set up when I am backpacking. However, on camino I leave off the filter altogether. Instead of the filter being added to the refill cap on the flexible water bottle, skip the filter and screw the refill adapter cap -- sans filter -- to the bottle after it is filled with water.
For refill bottles.... I use
extremely lightweight collapsible bottles that can hold up to 2 liters. Empty, they roll down to a small bundle that are easily stashed in an outside pocket.
Many times, I will carry 1/2 liter in the bottle as a quick backup if the weather or the distance between water refills dictates. So if I decide to, say, carry 1.5 liters on a longer stretch between water resupply points, I will fill the reservoir with 1 liter, and then carry 1/2 liter in the bottle and keeping the bottle partially collapsed. That also assures me that I do not need to visualize the amount in the reservoir to be assured of adequate water.
The refill container in the video is just one option. The refill adapter can also fit on a variety of bottled water containers, if so desired.
So those are the major issues that always seem to come up. There are other myths, but those are the major ones.