There is a lot of discussion around the non-superwash vs. superwash topic, so I wanted to answer some questions and hopefully address any concerns you may have with non-superwash yarn. I also have a highlight "Chatting SW/NSW" on my Instagram page with a lot of information on this topic!
What does "non-superwash" mean?
Wool is naturally composed of an outer layer of "scales" and an inner core. The scales are what people feel when yarn is described as "rustic", and what allows yarn to felt together by interlocking. "Superwash" is a term that describes the process altering the outer layer scales in some way. This process can describe anything from removing the scales completely or coating them with chemicals/plastic. The superwash process allows the yarn to be machine-washed as the yarn will no longer felt from drastic temperature changes or agitation. This is also why superwash yarn feels soft to the touch - because the outer layer of scales is essentially removed. "Non-superwash" just means that the yarn has not gone through the superwash process, so it is in its natural form.
Is non-superwash yarn soft?
In short, yes it definitely can be and sometimes even softer than superwash yarn.
They key to determining whether non-superwash yarn will be soft is the micron count. The micron count tells you the diameter of the fiber, which in turn is a measure of how fine or coarse the yarn is. A smaller micron count means the fiber is more fine and soft, whereas a larger micron count means the fiber is more coarse and "rustic" feeling. To put this into context, the average micron count of human hair is 100.
Here are the common categories of micron counts:
Superfine/extrafine/ultrafine/etc.: <20 microns
Fine: 20-29 microns
Medium/coarse: >30 microns
Yarn in the superfine category is considered "itch-free for all skin types", yarn in the fine category is considered "itch-free for most skin types", and yarn in the medium/coarse category is considered "itchy for most skin types". Personally, I have sensitive skin and I'm quite comfortable wearing anything under 23 microns and I think it is very comparable to how superwash yarn feels.
Here are some average micron counts for different types of wool:
Cashmere: 15-19 microns
Merino: 17-24 microns
Peruvian Highland: 24-29 microns
Corriedale: 24-32 microns
Border Leicester: 30-38 microns
Mohair: 24-45 microns
Always make sure to check the micron count if you're wondering how soft a certain yarn will be!
The crimp of the wool is another way to determine how soft the yarn may feel, though this information is harder to find. It is measured in crimps per inch, with a higher number meaning the diameter of the fiber is smaller and the yarn will be more "squishy".
Is non-superwash yarn durable?
Wool in general is very durable. Non-superwash yarn will also hold its shape better than superwash yarn. This is due to the fact that its felting properties are still present. With wear and washing, the scales of the wool will interlock slightly and provide more structure to your handmade items - it will not stretch or lose its shape as much over time as it would with superwash yarn.
Is non-superwash yarn really warm? Can I use it for warm weather makes?
Another natural property of wool is that it can regulate temperature very well! While it will definitely keep you warm in the colder months, you won't overheat because of it in the warmer months either (though it's best to use lighter weight wool in warmer months).
This is possible because of wool's ability to store moisture in vapor form. The natural crimp of the wool will trap air and little pores in the outer layer of the fiber will allow vapor to pass through to the inner core. This allows a layer of dry air to be kept next to your skin. Wool will naturally absorb moisture from the air of greater humidity and release it to the air of lesser humidity, so it works both ways to keep you warm and cool, depending on the temperature outside. Wool can absorb up to 30% of its weight in moisture before it feels wet to the touch, so just make sure to be reasonable about it and maybe don't try to wear a bulky sweater on a hot day!
The crimp of wool can also tell you how good of a temperature regulator the wool will be. A higher crimps per inch count means there are more pockets for trapped air, meaning it will be a better temperature regulator.
This information applies to non-superwash yarn because it still has all of its natural properties. With the alteration of the outer layer scales with superwash yarn, its temperature regulation is also affected and will not be as effective.
How often does non-superwash yarn need to be washed?
Wool naturally is anti-microbial! Lanolin, the natural wax in wool, contains properties that naturally kill the bacteria that cause odors in sweat. Because of wool's ability to remove moisture, any remaining bacteria will not have a damp environment to thrive. With superwash yarn, because the outer layer scales have been altered, it likely will not be as effective in killing bacteria. Therefore, non-superwash handmades don't actually need to be washed that often as long as they are worn reasonably, but use your judgement.