The complete guide
How to Choose a 25 Momme Silk Pillowcase
The problem with the pillowcase you already own
Most of us never think about pillowcases. They come in a pack with the sheets, they go on the pillow, and that is the end of it. Then one morning you notice your hair looks like it has been in a fight, or there is a crease down one cheek that takes until lunchtime to fade, and you start wondering whether the fabric has anything to do with it.
It does, a bit. A standard cotton pillowcase is a woven grid of short fibres with a slightly rough surface. Run your fingertip across it slowly and you can feel the texture. Your face and hair spend seven or eight hours dragging across that surface every night, turning over, pressing in, turning back. Silk is a long continuous filament with a smooth face, so the same movement produces less friction. That is the whole mechanism. No magic, just a smoother surface.
The second thing people notice is temperature. Silk feels cool when you first lie down. Whether it stays that way through the night depends on your room, your pillow and your duvet, but that first contact is real and it is why a lot of people switch over in summer.
What momme actually tells you
Cotton gets described by thread count. Silk gets described by momme, usually written as mm after the number, which is confusing because it has nothing to do with millimetres. Momme measures weight. Specifically it describes how much a given area of the fabric weighs, so a higher number means more silk packed into the same space.
Most silk pillowcases sold online sit at 19 momme. That is the industry baseline, and it is perfectly serviceable. This one is 25 momme, which is a meaningful step up. You can feel it immediately. A 19 momme case is light and slippery. A 25 momme case has heft. It stays where you put it on the bed instead of sliding around, and it drapes over the pillow with a bit of weight rather than clinging.
There is a practical side to the extra density too. More fibre in the weave generally means the fabric copes better with repeated washing and with the daily tug of being pulled on and off a pillow. If you are comparing options and trying to work out where to spend, momme is the single number worth paying attention to. Anything from 22 upward is in solid territory.
Why undyed matters to some people
This case is natural white, and that colour is the silk's own. No dye bath, no optical brightener. The result is a soft, slightly creamy white rather than the hard fluorescent white you get from heavily processed cotton.
There are two reasons people go looking for an undyed option. The first is purely visual. A natural white sits comfortably next to linen, oatmeal, stone and other undyed bedding, where a bright white can look cold and out of place. The second is practical. There is no added colour in the fabric, so there is nothing to transfer onto a pale pillow or onto other items in the wash. If you have ever pulled a load out of the machine and found a faint tint on your sheets, you will appreciate not having to think about it.
The trade-off is that a natural white will not match a bright white sheet set exactly. If the rest of your bedding is crisp hotel white, there will be a slight difference in tone. Some people like the layered look that creates. Others would rather everything matched. Worth deciding before you order.
The closure, and why it is not a small detail
Pillowcases close in one of three ways. Open end, zip, or envelope flap. The open end is the cheapest and the pillow works its way out by about three in the morning. The zip holds well but puts a strip of hardware somewhere near your head, and it catches hair.
This one uses an envelope closure, which means an extra panel of fabric folds back inside the case and holds the pillow in. No hardware, nothing to snag, nothing to press into your face. The opening here is on the side rather than the end, and it is set slightly off centre.
That offset is what lets the case double as a sham. Looked at from the front, there is no visible opening and no gap, just a clean rectangle of silk. So you can sleep on it at night and leave it looking tidy on the made bed during the day without owning two sets of covers. It is a small design decision that quietly solves two problems.
Getting the size right
This is a queen case at 71.1 cm long by 50.8 cm wide. That is the measurement that matters, so check it against the pillow you actually own rather than trusting the label on the pillow.
A standard pillow is shorter. It will fit inside this case, but there will be slack at the end and the pillow will shift about. A king pillow is longer and simply will not go in. Pillow sizing is not perfectly consistent between brands either, so a tape measure is the only reliable method. Lay your pillow flat, measure it end to end and side to side, and compare.
If you are buying for a queen bed and you want a matched pair, remember this listing is for one case. Two pillows means two orders.
Looking after it
Silk is a protein fibre, closer to wool or hair than to cotton. That shapes how you wash it.
Dry cleaning or hand washing in cool water with a gentle detergent are the two best methods. Hand washing is easier than it sounds. Fill a basin with cool water, add a small amount of detergent made for delicates, swirl the case through for a minute or two, rinse until the water runs clear, then press the water out without wringing.
Machine washing is allowed if you use the delicate cycle and put the case inside a mesh laundry bag first. The bag matters more than people expect. It stops the silk from being dragged against zips, buttons and the drum itself.
Three things to avoid. No bleach, which attacks protein fibres directly. No fabric softener, which leaves a coating that dulls the natural sheen. No tumble dryer, because heat and tumbling together are hard on silk. Lay the case flat to dry, out of direct sunlight, and it will be ready in a few hours.
If it needs pressing, use the lowest silk setting on the iron while the fabric is still slightly damp, and work on the reverse side. Most of the time you will not need to bother.
Who this suits
Someone who has tried a cheap silk case and found it too flimsy. Someone with long hair who is tired of waking up to tangles. Someone who runs warm at night. Someone decorating a bedroom in undyed and natural tones who does not want a bright white interruption. And honestly, someone buying a present and not wanting to guess at colour preferences, because a natural white works almost anywhere.
Who it does not suit: anyone who wants to throw everything in a hot wash and a dryer without thinking about it. Silk needs a slightly gentler routine. It is not difficult, but it is a routine.
The short version
25 momme is a heavier, denser silk than the 19 momme standard, and you can feel the difference straight away. The colour is the silk's own natural white, with no dye involved. Silk covers both faces of the case, so it does not matter which way you flip the pillow. The side-entry envelope closure keeps the surface smooth and lets the case work as a sham as well. Size is queen at 71.1 cm by 50.8 cm, so measure your pillow first. Wash it gently, keep it out of the dryer, and it will be part of your bed for a long time.