I have a large stainless steel martini shaker. Lately, I discovered that I really like iced green tea, and I’ve been using the shaker to make it. My usual method is to make extra-strong green tea (I know, it’s almost a contradiction in terms), using a small teapot that holds maybe three of those old fashioned small cups. Then I fill the martini shaker about half-full of ice, and pour in the tea. At the end of this step it’s slightly tepid so I put it in the refrigerator, where by late afternoon it gets chilled to the proper temperature.

But making ice is sort of a hassle. So today, I thought, why not just fill the shaker with water, and put that in the freezer? Actually, I thought of it last night and it’s been in the refrigerator all night. But now I want to get it down to near-freezing, so it’s been in the freezer for about an hour.

My question is, will the expansion of the water as it freezes deform and ruin the martini shaker? Or does freezing water naturally expand in the direction that offers the least resistance? I’ve never lived in a cold climate, so I’m not sure exactly how freezing water causes pipes to burst.

Water will expand when it freezes, but it will move into the area, as you say, of least resistance. As long as you don’t fill the shaker all the way, you should be fine. I generally leave about 1/3-1/4 of the vessel empty, but I’m sure someone here knows exactly how much water expands when it freezes and can be more precise about that.

Okay, here’s what I did. I happen to be holding in my hand a stainless steel martini shaker. I measured the top diameter as being 3.375", the bottom as 2.375" and the height to the fill line as 7.5".

The volume of a frustrum is (1/3) Pih(R^2+r^2+R*r) where h is the height, R is the radius of the larger diameter and r is the radius of the smaller. After calculation that gives a volume of 49.2 in^3.

A cubic inch of ice weighs 0.033237 pounds, therefore, I have room in my cocktail shaker for 1.64 pounds of ice. A cubic inch of water weighs 0.036127 pounds, so the shaker has room for 1.78 pounds of water. I filled it with water and weighed it at 1.75 pounds, close enough for the accuracy of the tools I was using.

So, the question is, how much water can I put in there before freezing? Well, I can put 1.64 pounds of water in, which has a volume of 45.25 in^3. Putting the 45.25 in^3 back in our volume of a frustrum formula, I come up with an h of 6.9 inches. This doesn’t account for the fact that the large diameter at 6.9 inches high is slightly less than the 3.375 inch diameter measured at 7.5 inches high, so you can actually put in a little more than that.

That’s going to take calculus to solve, and there’s a limit to how much work I want to go through to make your green tea cold.

A block of shaker-shaped ice is going to take forever to thaw. And you’re not going to get much tea in there if you almost fill it with the water. Ice cubes at least have air space between them where the tea can go. An ice block isn’t going to make room for anything else.

Just shake the tea with the ice cubes in your martini shaker. That’s what the martini shaker is for in the first place. Then pour over new cubes if you like. Easy peasy chilly tea.