Strainer, fine mesh and double straining
Straining is not just removing ice. It is the last texture decision you make before serving, and what separates a silky drink from one with shards floating in it.
After shaking or stirring, the liquid carries ice shards, bits of herb, citrus pulp and sometimes traces of egg white. What you do in the next five seconds decides the final texture. There are three tools, and each has its moment.
Hawthorne, julep and fine mesh
The hawthorne is the one with a spring around it and two or three prongs. It sits on the shaker and handles everything shaken. The spring does the work: it holds back the ice and most of the solids. If yours has a side tab, push it in to close the gap and filter finer.
The julep is a perforated disc shaped like a large spoon. It goes inside the mixing glass, holding the ice back as you pour. It is the natural partner for stirred drinks, where there are no shards to catch because the ice was never broken up.
The fine mesh is an ordinary tea strainer. It does not replace the other two: it is used in addition, held under the pour as you strain. It catches whatever the hawthorne lets through.
When to double strain
The rule is simple: if the drink is served without ice, always double strain. In a clean, clear glass a single floating shard is visible, and it also melts and upsets the dilution you just calculated.
It is also worth doing whenever you have muddled herbs, used fresh fruit or added egg white. For a drink served over ice, however, double straining is optional: anything that slips through will be hidden and will not change the texture.
A detail almost nobody checks
The tension of a hawthorne spring can be adjusted. Stretch it slightly and the coils separate, filtering coarser; compress it and it filters finer. Cheap springs slacken with use and eventually let everything through. When you notice your drinks coming out with more sediment than usual, that is the reason, and a replacement costs very little.