Just to let you know… I’ve made the decision to switch the absorbent core material I use…
I was using a 70% bamboo / 30% organic cotton fleece (where possible, and occasionally a non-organic cotton blend one when I couldn’t get the organic). From now on I will be using a 70% bamboo / 30% hemp fleece for my pad cores.
As usual, all my product listings list the fabrics used, so you can see which core fabric is used in which pads. Some pads on my site still have the bamboo/cotton fleece core, some have bamboo/hemp.
While hemp is more absorbent than cotton, the bamboo/cotton fleece I was using is 400gsm (heavy-weight), whereas the bamboo/hemp fleece is 320gsm (medium-weight), the fabric is not as thick. I believe my pad layering should be sufficient though that this difference should not be noticeable, particularly in pads with PUL. In my non-waterproofed pads, I add an extra layer of flannelette in those anyway, but you may need to check for leaks to make sure the new pads function the same way the old pads do.
I’ve done some calculations on pad absorbency at the bottom of this post, which you may find interesting.
The slight reduction in absorbency is something I have thought very hard about, but I felt that it was something I needed to do, in order to fit my lifestyle philosophy.
The reason I have switched is that while organic cotton is quite an eco-friendly fabric, I personally feel (based on reports I’ve read) that hemp is a more eco-friendly fabric than even organic cotton (and certainly than non-organic cotton), also the hemp/cotton (non-organic) blend I would sometimes buy is also bleached, whereas the bamboo/hemp fabric is not.
I really feel that it is important to help support the hemp textiles industry, as I feel this is a very sustainable and useful crop, that is not being used enough!
So I feel the bamboo/hemp fleece provides a good mix of the soft and absorbent bamboo with the durable and eco-friendly hemp.
Hemp crops require half as much land for the yield than cotton, hemp also requires half as much water to grow. In processing, cotton uses more than 4 times more water than hemp. So even taking pesticides out of the equation (regular cotton crops require a lot of pesticides, but organic cotton and hemp do not)…. hemp still appears to be a far better crop for the environment. So I feel we should support hemp textiles over cotton.
To test the absorbencies of different fabrics, I took 10cm square pieces of the (prewashed) bamboo/cotton fleece and the bamboo/hemp fleece. (I also tested flannelette and zorb too)
I compared the weight of the samples when dry, and then let them absorb as much hot water as they can (left them soaking in a bowl of water for a minute, squeezed the water out then put it back in to absorb more, repeated then left that to soak for a few more minutes). I then lifted them out of the bowl by one corner and waited until they stopped dripping – and then weighed them to see how much liquid they had absorbed. (comparing the wet weight to the dry weight)
Results are here:
Zorb (Not sure which version) – Dry 3g – Wet 25g – Absorbed^ 22g
Bamboo/Cotton fleece (400gsm) – Dry 4g – Wet 23g – Absorbed 19g
Cotton flannelette (2 layers) – Dry 4g – Wet 19g – Absorbed 15g
Bamboo/Hemp fleece 320gsm – Dry 3.5g* – Wet 19g – Absorbed 15.5g
Hemp/Cotton fleece 350gsm – Dry 4g – Wet 19g – Absorbed 15g
^ The zorb initially held a lot of water, but (like a sponge), the water just poured out of it for a long time. So while it can hold onto a lot of liquid, unlike the natural fibres, it can’t keep it all (it’s not “absorbing” as such). It’s not actually trapping most of it inside the fibres, the water will stay there only if there is nowhere else for it to go. (Which is why it can “compression leak”).
* my scales are only accurate to full grams, this sample kept bouncing between 3 and 4 grams. So I’m putting it as 3.5 g
So ultimately, in a 25cm long pad, the core inside is about 5cm wide by 20cm long, so 1 layer of core would be about the equivalent to one of the 10×10 squares of fabric I tested.
A “regular” absorbency 25cm (Neophyte) pad would have 2 layers of core fabric (so 2 swatches worth), plus I do a full layer of flannelette (so lets add on the flannelette swatch absorbency since the pad shape is single layer, but larger than a 10×10 square). So a new bamboo/hemp pad would have about 46g absorbency, the old bamboo/cotton core pad have about 53g absorbency. A difference of 7mls.
That is only how much the pad core will absorb without dripping though. The amount of liquid it will hold in total, especially in a pad with PUL where it won’t leak through even when the core is sodden, could easily be twice that.
To put that into reference for menstrual flow, the “average” woman reportedly has a flow of about 10-80ml over their entire period, and you’re expected to change your pad every 3-4 hours for hygiene reasons. So even if you have a heavier than “normal” flow that is double that amount….. a regular day may only be about 30mls over the whole day. So you should be well covered for several hours with even a regular absorbency Neophyte pad with PUL😀