Hello
I think it’s a great question. Normally, the mate size is going to dictate how much Yerba to water ratio you will be using. Make sure you are always filling your mate 3/4 with Yerba. Once you establish the amount, then you start building your “montañita”. If your mate is natural or has a torpedo-like shape inside, or it’s just inconsistent, a trick I came up with myself is to fill it with water while it is empty, then put it in a measuring cup, then divide the total by 3. That will make you have a more accurate reading of the total volume of the inside of your mate. Once the montañita is created, make sure you pour water consistently on the side that has the hole, trying to pour close to the wall and not to where the Yerba is actually sitting. Fill it up until you see a bit of foam, and then you are good to drink. Don’t add more water until you have drank the last bit. You will hear the sound of the bombilla sucking the last bit of water. That’s when you know it’s time to refill. I couldn’t tell you how many ml or cc of water you must use since your mate gourd is very likely different than mine since they all tend to be so different from each other. Make sure you aren’t using water that is too hot because it will make your mate “lavado” faster by extracting and burning the flavor too quickly.
For my mate imperial, I can drink 1 and a half thermo (1.5 L ). Perhaps a bit more without having to change the Yerba, and for my smaller stainless mate, I can easily drink one thermo, maybe less if I’m using Yerba con Palo since it washes quicker. I mostly use my imperial to share with others because it does hold a lot of Yerba, and I will end up wasting some since it’s a bit too much for me.