Hot, soapy water really is that bitch. It’s all you need to clean most things. But, in some cases, it does its job a little too well, especially if you’re dealing with greasy pots or pans.
According to to Doyle James, president of Mr. Rooter Plumbing, who spoke to The Kitchn about this sticky issue, cold water is actually the better choice when hand-washing oily or fatty residue off of your cookware. Hot water melts the grease, which then solidifies when it cools in your pipes, coating them with fat and — eventually — causing a clog. Cold water, James explains, does the opposite:
However, cold water helps keep the grease solid, so it can travel easily and efficiently through the pipes without getting clogged. “When fat, oil, and grease meet the cold water, it quickly solidifies, [and] the principles of water and gravity take over and wash it away,” James says.
Does this mean you can wash lots of fat and grease down your drain, as long as you use cold water? No, it does not — you should still pour or wipe out as much fat, oil, and grease as you can before using any soap or water (or putting your pan in the dishwasher, for that matter). I keep an old vegetable oil bottle under my sink for this exact purpose.
It may seem like tiny amounts of butter, lard, or congealed bacon fat aren’t “that big of a deal,” but lots of tiny greasy bits can accumulate into a large, unmovable greasy mound, and no one — not you, nor your neighbours, nor your wallet — wants that.
So wipe out your pans, and wipe them out well, and wash away any thin, greasy films with cold water — and plenty of soap, which keeps the grease emulsified with surfactants — to keep the residue from coating your pipes and ruining your life (if only for a little bit).