How Absorbent Are Your Inserts?

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This blog post originally appeared on I Dream of Diapers, a cloth diaper blog run by our own Kinsey Marie. It is reposted here with Kinsey’s permission.


How Absorbent Are Your Cloth Diaper Inserts? Let’s Compare Them

Everyone always wants to know what inserts are more absorbent for their cloth diapers. Well, I decided to run a real comparison among the 9 different inserts I own, and I’m thrilled to share the results. I was actually quite surprised by the performance of a few of them.

The Contenders: 2-layer Hemp liner, Gerber Prefold, KaWaii Microfiber, FST (Flour Sack Towel), 4-layer Bamboo, Alva CBI, Babies R Us Prefold, generic unknown CBI, and a flannel receiving blanket.

Method used: Water displacement in a 1 quart measuring glass. I timed how long it took to initially absorb the water, then timed one full minute after initial saturation to allow for full absorption. I noted any physical water displacement by the insert due to incomplete absorption. Once fully saturated, I lifted out each insert and waited for them to stop draining/dripping. Then I noted how much water was retained in the insert instead of the measuring cup after being wrung out.

2-layer Hemp liner 55% hemp/45% organic cotton 13x5in.~ You can see here how thin this is. I really only tested this because I have it, and because it’s been a great booster and I wanted to see exactly how much it held. This is not a substantial insert on its own and likely is not a full representation of the absorbent capacity of hemp; it really is just a doubler. I will say that it absorbed way, way faster than I thought hemp could! It sucked up the water right away. No water displacement while saturating; retained no water after being wrung out. Initial Saturation time: 20 seconds. Full capacity: 4 ounces.

Gerber Birdseye 3-ply Prefold 7.5 x 11 x 2.5in.~  Gerber does not have a great reputation for making absorbent prefolds. I did not expect much from them, and they delivered. It took a bit to saturate, and after lifting the prefold out of the water, it drained out a ton for what felt like forever. My arm got tired. All of that for it to be the least absorbent insert option. No displacement while saturating; retained 1/2cup wrung out. Initial Saturation: 45 seconds. Full capacity: 7 ounces.

3-layer Kawaii Microfiber 13x5in~ This is a standard microfiber insert. I was suprised that it took a bit to initially saturate, but that is due to the need for compression. Once I pushed the insert in, it absorbed better. There was no displacement of water once saturated, and no retained water once wrung out. Initial saturation time: 50 seconds. Full capacity: 8 ounces

Flour Sack Towel (FST), Walmart Mainstays brand~ I’ve joined the chorus in singing of how good these are as an insert option. In my experience, they had absorbed just as well, if not better, than my 3-layer MF. I was happy to test the absorbency of flour sack towels against microfiber and the other options, and I was glad to see everyone was right. It absorbs just as much as a microfiber, but actually works better because it isn’t prone to compression leaks. The FST saturated faster than the microfiber, which surprised me, and held exactly the same amount. There was no water displacement, and it didn’t retain any water once wrung out. Initial Saturation time: 45 seconds. Full capacity: 8 ounces

4-layer Bamboo, Sunbaby XL 13x5in~ Sunbaby does not advertise the exact bamboo/cotton percentage here if there is any cotton. I had high hopes for this because my experience with it has been good, even if it occasionally shifts inside the diaper. It saturated quickly, but the bamboo didn’t absorb as much as I thought it would compared to the microfiber. There was no displacement in the glass, and it retained 1/2 cup of water when wrung out. Initial Saturation time: 30 seconds. Full capacity: 9 ounces.

5-layer Charcoal Bamboo Alva Microfiber Blend Insert 13×5.25 in~ There is a lot of hype about CBIs. Good and bad. You either love or hate them, there isn’t much in between. These are 3 layers of microfiber sandwiched between 2 layers of Charcoal Bamboo. Some say the bamboo portion is not very absorbent because it is fleeced into polyester. I did notice that the saturation time was a little longer because it needed some compression to fully saturate. It also displaced almost 4 ounces of water, indicating that there is a portion of it that did not totally absorb. Given that, I was surprised to find it was still very absorbent (more than just 3-layer microfiber for sure) and it even retained 4 ounces of water after being wrung out.  Initial Saturation time: 50 seconds. Full capacity: 10 ounces.

Babies R Us 3-ply Prefold 14x20in~ This is a standard prefold that typically is used for burp rags. I converted most of mine to fitteds and added a soaker, but was curious what this prefold would absorb on its own. It took a very long time to drain the excess, but it didn’t dump out as quickly as the Gerber did. There was no water displacement and it retained about 5 ounces of water when wrung out. Initial Saturation time: 40 seconds. Full capacity: 10 ounces.

5-layer Charcoal Bamboo Blend Generic Insert 13.5×5.5in~ This is a no-brand CBI that I got through Alli Morris of The Awesome Ninja Queens co-op on Facebook. This was the first buy with updated materials from the supplier, and is 3 layers of microfiber sandwiched between 2 layers of charcoal bamboo just like the Alva, but it is constructed differently. It is very plush, and does not have any sewing inside the insert, only white surging around it. I was very, very surprised at its capacity. It saturated quicker than the Alva CBI and the Microfiber, there was no displacement at all, and I could easily see where the water was rising through the insert as it saturated. I wrung it out the best I could, but it still retained 1/2cup of water. It’s apparent that the materials in this generic brand are superior to the Alva, and this CBI almost tied for first place in its capacity to absorb. Initial Saturation time: 40 seconds. Full capacity: 12 ounces.

Flannel Receiving Blanket 28x31in~ I know that many people use receiving blankets as flats and also as inserts, so I wanted to test their absorbency in comparison to other standard inserts or prefolds. Due to its size, it took a little time to saturate, but it did absorb quickly. There was no displacement of water while saturating, and it retained 1/2cup of water once wrung out. Initial Saturation time: 45 seconds. Full capacity: 13 ounces

All inserts were prepped and have been in my rotation for a while. I have no repelling issues or hard mineral buildup. There are many variables to the success of an experiment like this one, and obviously I don’t have a lab, so obviously this isn’t a perfect test. I will be testing more inserts in the future as I have access to them, but I believe this gives a good baseline with which to compare future cloth diaper inserts and their absorbency. I hope this helps you better understand the absorbency of different inserts. Let me know if your experience is similar to my experiment!