KeepCups now come in five sizes - 4oz, 6oz, 8oz, 12oz and 16oz, we call them XS, SiX, S, M and L. Part of our pitch is that we replicate internal volumes to ensure your coffee is neither too strong, nor too weak.
We have just launched the SiX a 6oz version of the KeepCup - a stronger version of the 8oz that more accurately reflects the internal volumes of inhouse vessels - Duralex glasses or ceramic cups.
No sooner have we done this than we are getting requests for 10oz, a stronger version of a 12oz coffee. We are trying to create less cups not more - is there another solution?
Understanding sizes and volumes is complicated by the fact that fluid ounces can be US or Imperial and therefore convert differently to millilitres.
Being from the an old colony, we chose an Imperial conversion for KeepCups (plus we were big Star Wars fans so we knew better than to confront the Imperial forces). The volume is less, resulting in a stronger coffee - so we think its a good result.
The images below demonstrate the differences. Here I must confess that, whilst in sporting teams I might be chosen early in the selection, I am not the go-to girl for precision, so apologies in advance if there are any errors. Andhings became slightly more complex when a young assistant came to lend a hand:
We created the KeepCups with 'ullage'. The word comes from the practice of not filling wine barrels beyond the stopper hole, and in our instance refers to a deliberate gap between the beverage and the top of the cup. There is an ullage marker in all KeepCups.
You can see that as far as Imperial ounces go, our measurements are accurate and meet our prescribed fill line:
The good news is that for coffee makers taking an Imperial conversion, if you fill the 8oz KeepCup to the brim (which baristas often do), you get a 10oz coffee:
It's a little more ambiguous for the US fluid ounces. At this point, I get to use one of the only words I remember from science at school, meniscus, referring to the convex or concave curve on the surface of a liquid when totally filled, because that's what happens when you fill 10oz of US millage in an 8oz small KeepCup.
Not so great a result with the 8oz I got from my local cafe Two Bob (thanks Spock). My, what an impressive meniscus!
A comparison of US conversion with an 8oz disposable cup :
KeepCups are awesome. They are a workable, fun and sustainable alternative to the disposable cup. If you want a 10oz, fill a small keepCup to the brim, if you want an 8oz fill to the line marked.
Reuse or refrain. Salute the Reuser!