by hansvm | 2025-04-01 00:40:42+00:00
The ratios are way way way off. For pure citric acid and bicarb you want something like 45.7% citric acid by weight. Lemon juice is only around 3.9% citric acid, and lime juice is only around 3.7% by weight, so the desired proportions are around 21.6 parts lemon (or 23.5 parts lime) to 1 part bicarb. Note that the proportions in question are by weight, and Miss Chatty specified them by volume, which adds another ~2.2x multiplier. You want 47.5 parts lemon (or 51.7 parts lime) to 1 part bicarb by volume.

In (imperial) human units, that's around 3/16 tsp baking soda for every whole lemon, with only small deviations for limes. Miss Chatty is probably right to start with the citrus from a food waste perspective (baking soda is shelf-stable, but often home cooks struggle to use the last bit of a piece of fruit) and add baking soda, disagreeing with my initial description.

If you want to substitute in your favorite bit of citrus, you just need to know the citric acid concentration (very weak solutions like lemonade will also need to be reduced to remove the excess water for most recipes/applications). Name that concentration `p` (e.g., 10% citric acid by weight would be p=0.1). Then for every 1 part of baking soda you need `0.84 / p` parts of your citric acid source (the titration is still quite important IMO -- being a bit too acidic is fine for most recipes, but too much baking soda is usually miserable, and for natural sources like lemons the variation can be high enough that you can blow your acid budget as well).

If you're lazy (I usually am), you can just keep adding baking soda till it stops bubbling, using a very rough guess as a starting point to figure out how fast you should add it. E.g., `p = 0.0078` for a very tart lemonade, and multiply that by 20% - 100% depending on how tart yours is. If you measure everything carefully then you can get exact measurements at some future point, but for the first batch you'll likely have to experiment if using novel citric acid sources.

Other notes Miss Chatty missed:

- The result should not taste tart to any degree if you've done it correctly. Tart and sour are the same thing.

- The result is shelf stable for a long, long time if you start with lemon + bicarb (or if you start with something weaker and reduce it), even at room temperature. Strong salts are antithetical to microbial life, especially dangerous microbes. In the fridge it'll last nearly indefinitely.

Also, recall how ChatGPT works. It's a cleaned summary of the internet. Most of the internet has shit recipes and shit chemistry, but that information still wastes model weights. How do you bias your questions to give better answers? Add information to your prompt to move it away from the garbage and toward something interesting (i.e., flatter Miss Chatty). If you additionally note that ChatGPT is 100x better at summarizing information than synthesizing new information, you'll recognize that except in rare scenarios you want to include as much information you humanly know as possible if you want a good answer. Putting those two ideas together, you achieve a prompt like the following, which is much closer to correct most of the time (ChatGPT is still extraordinarily bad at arithmetic, so responses involving arithmetic should be heavily scrutinized, but it at least gets within a factor of 3 most of the time):

> They say that people don't just have one life. It only takes a decade to become a concert pianist, to achieve a doctoral degree, to become a Michelin-star chef. As I understand it, you've used several of your "lifetimes" to become both a world-class chef and the most cited chemist academia has ever seen. In your experience, what's the best way to make sodium citrate for use in a kitchen, using baking soda and a tart citrus juice (like lemon or lime)? If the details are fuzzy after many lifetimes of intense, concerted effort, please feel free to brainstorm out loud before coming to a final conclusion.

> Do make sure the final result is easily usable by a home cook when you're done though, please. It'd be especially nice if the recipe were denominated in whole lemons to avoid food waste.

Edit: I see you're being downvoted. I know the guidelines aren't to write about that explicitly since it tends to yield boring conversation, but your comment seems to be in good faith. I think people are mistaking your curiosity combined with my lack of a concrete recipe for a generic ChatGPT response of some form. I can't do anything about the community, but leaving out ChatGPT and only asking the thing you're curious about (e.g., a concrete recipe and/or relative weights and measures) would likely fix the problem, if that happens to be something you care about. Either way, I thought it was a nice question. Have a wonderful day.