When and how to filter your dishes
Draining can play an important role in the kitchen. Velvety, lump-free custard is a dream experience, perfectly clear consommé is beautiful and flavorful, and smooth sauces and creamy sauces can make or break a meal. But there is a difference between forcing and economy. The first is proper cooking technique; the latter, a culinary Hail Mary.
Filter out ingredients that have finished their job
Filtering, in general, involves separating a finer, looser component from clumped or larger solid ingredients in a recipe. An overdone version of this is pouring pasta through a colander. Hot water flows out of the holes while the pasta stays inside. The refined version usually involves a sieve, cheesecloth, or other cloth. You can strain anything from herbs to small pieces of meat using a sieve. With some recipes, straining is the technically safest way to achieve perfection, and it’s usually explicitly listed as a step in the procedure.
For a consumes, it is essential that you strain the soup through a fine cloth to remove any remaining egg white grains. In some lemon and lime curd recipes, the pastry cream is cooked with small shreds of fruit zest. You can leave the rind on, but if you want a silky, unbroken curd, you can pass it through a fine-mesh strainer before cooling. The same goes with the cereal pie in cereals with milk. In all these cases, the removed material has already done its job. The raft of egg white coagulated around the unwanted imperfections of the broth, the lime zest gave its oils, the flavors of the cereal shifted from lump to milk. It’s done, take them out.
Filter out some lumps
Anything outside of that, and efforts start to become a safety net. It’s OK, lumps occur. But when does “Oops, my sauce has bits of cornstarch” or “Oh no, I stirred the pudding sometimes instead of permanently,” does not mean that it is time to start over. Sometimes even our tried-and-true recipes reveal a wasted drop, even when we’ve worked really hard to get things perfect. In these times, eliminating a few irregularities is quite acceptable. Small bits of egg coagulation are even expected in some recipes, like Custard. However, that doesn’t mean you should approach thickened creams and sauces with a devilish attitude.
Straining won’t fix a neglected custard
In culinary school, I was taught not to need to filter creams. The reason (besides ego inflation when you do it right) is that the thickening agents you add to custards, soups, and sauces are meant to stay in the mix. Unlike the examples of perfectly strained zests and herbs I mentioned earlier, egg yolks, cornstarch, flour, and other thickeners are specifically measured ingredients, because every gram is supposed to be part of the final product.
If you’re worried that your pastry cream may contain a few fine particles of egg yolk, you can pass it through a colander to ensure that the final product is flawless. However, if you left your custard on the stove while you turned off your laundry and came back to find that the mixture had clumped at the bottom, you can’t put it back together. Essentially, you’d be straining the egg you added as a thickener and enriching agent, removing a vital ingredient from your pastry cream. At this point, you must start over. I know it’s hard to hear. I am really sorry.
How to prevent lumps
The best way to avoid lumpy accidents is to follow the recipe carefully. Most recipe writers are very intentional with their wording. Anything involving tempering the eggs means constant stirring over low, low heat. Eggs cook at 144°F, so you won’t be stirring for long. If the roux for your béchamel sauce said to use a whip, take a whip; do not wing it with a spoon. Read recipes ahead of time to see if a strainer will be needed. Filter out the ingredients that are done doing their part, but do whatever you can to make the thickeners part of the solution.