A Simple Coconut Curry Salmon and Some Food Science

I shy away from posting the simple stuff we cook at home, but this one earns it. The quality-to-simplicity ratio is high, and the food science lesson I stumbled into was worth sharing.

With a wedding around the corner, many of the dishes that we cook tend to be far more simple than what I typically post might otherwise suggest. I decided recently that these would be good opportunities to focus on simple protein-, sauce-, and vegetable-forward recipes that incorporate a technique or a sauce - or both - that allow me to continue practicing and learning in the kitchen.

The inspiration for this initially came from a barely-cooked salmon dish that I had at Le Bernardin, the recipe for which Eric Ripert details on his now-abandoned site, Avec Eric. While mucking about on the Internet thinking about this, I came across another similar recipe by Eric, this time for Bon Appetit, which I had more interest in cooking that night.

The gist of the recipe is incredibly simple. You cook a salmon "unilaterally" at a moderate temperature to medium-rare to create a custard-like texture for the fish and surround it with an interesting sauce.

After making this dish, I was a bit underwhelmed by the flavor of the sauce. It came through, but not with the depth I expected from a curry. I started thinking about what in the sauce may have caused this and why, and thus came about our little food science lesson.

I'd recently seen something that Kenji posted about sauce reductions, notably that you lose a good bit of aromatics when reducing a sauce at higher temperatures. In simple terms, the strong bubbling pushing all of that steam you see off into the air is responsible for that. Most people reduce this way because it is considerably more efficient; if you were strictly trying to maximize flavor, you would reduce slowly at lower temperatures, but it would take considerably longer than you might consider ideal for home cooking.

I came to think about how to improve the sauce with that in mind, but it became clear quickly that this was both a reduction issue and a fat content issue. When adding the shallot, garlic, and ginger to the pan, you are sweating them, then reducing them in the white wine initially. You have built that aromatic profile in your sauce already, then comes the curry powder, and the addition of the coconut milk is where you hope to add some texture and a bit of flavor without losing your aromatics. Though you might theoretically save some aromatics during the reduction process with the wine, the volume is small, and this is unlikely to be where I lost flavor.

After adding the coconut milk, I continued to simmer my sauce, noticing that it was thinner than I had hoped and thinking that a continued reduction would help me reach the desired consistency. Which is precisely where my problem occurred. We want the aromatics to work their way into the fat, but we know we are losing aromatics the longer we simmer. My sauce was already basically reduced before adding the coconut milk, so though I may have been thickening it some, I was losing aromatics far faster than I was gaining thickness. And so it is abundantly clear, at some point I was not trading anything off at all; the fat phase was reaching saturation, so I was only pissing away useful aromatics.

And the best part? It turns out I was using a coconut milk designed primarily for drinking, not for cooking. I had grabbed a coconut milk from the store that was something like 2% fat where we wanted the canned versions that are upwards of 25% fat. So, we learned a bunch of stuff about aromatics in fats and reductions where we may have otherwise not even been curious.

The margins matter when you're genuinely trying to maximize flavor, and they're worth understanding. Here is what that looks like, if you would like to see it and read it more clearly, with a quote attributed to no one that I think was entirely made up for the purposes of the visualization.