So… why? Why does doubling portions always mean doubling each ingredient? Obviously this maintains the proportionality between ingredients, by that just moves the goalposts, why is maintaining proportionality important?
For a few things, like salt, we may not do it. If something requires a pinch of salt, we usually just add a pinch for any recipe size until you start getting to huge industrial batches, but the times you do seem very rare.
Why are there never ingredients that scale, say e[sup]2n[/sup] where n is the number of portions?
I know this probably seems like an absurdly stupid question, but I often wonder why it never seems to turn out that ingredients become less important/prevalent the bigger the batch and things like that, or ingredients that grow to dominate in bigger batches. Obviously there’s a reason, but I’m not entirely sure why that basically never happens.
So why are there not recipes where for every n parts water, I need n[sup]2[/sup] parts corn starch, or something like that? Maybe it does happen, but linear scaling is a good enough approximation for home cooking and becomes a legitimate thing in industrial batches?
I don’t have an answer for why this happens most of the time, but as an example of where this doesn’t happen: for an exceptionally large batch of beer, you don’t necessarily multiply the amount of yeast used by the size relative to a normal batch. So, if you had one of those big 55 gallon industrial fermenters, and you wanted to make up 50 gallons of beer, you wouldn’t have to use 10 times as much yeast as you would for one 5 gallon batch. It’s recommended that you do, in order to get things going, but if you only put in 3 or 4 times as much yeast, it’d still work; it’d just take longer.
You don’t for oatmeal, or poleta or grits. Why? I’m not entirely sure; I’ve never tried doubling it; I suspect it has to do with how much liquid the starches can thicken. And when you get to very large batches of rice, it’s not suggested to simply double. Doubling jam recipes will notoriously lead to rubbery jam.
There are recipes that “don’t double well”, which are better served by making two separate batches, but you can make a larger batch if you don’t double everything. Cooking allows a lot more wiggle room than baking. Too much or too little is rarely a big deal, but I’ve had some overspiced dishes from people that simply double every spice; some spices become overpowering. Baking is where I’ve seen more of the “doesn’t double well” recipes, 'cause chemistry.
Think of it the other way. Suppose you want to feed 12 people some recipe. Why should making it in one batch to feed 12 or two batches to feed 6 each or four batches to feed 3 each require different total inputs.
Maybe if you’re using volume measurements, but weight measurements, I’ve almost always seen them expressed in baker’s percentages, so they’re easy to scale up and down as needed.
My guess is that by volume measurements aren’t nearly exact enough at small scales to scale up well. I have a few non-baking recipes that I keep with “by weight” ratios so I can easily go up and down and not worry about how much fudge factor is involved and I can be consistent (for example, all my sausage recipes I have written down by weight, as sometimes I’m making 15 pounds of sausage, and other times I only want to make 2 pounds, and it’s just easier to deal with and get the flavor I’m aiming for.)
I can think of several potential reasons. Say you need some reaction to occur, but it only requires a critical mass of some compounds to happen, and above that it’s useless. Or things like yeast (like Ethrilist mentioned) are bacteria, and all you need is enough to maintain a stable, growing population, which (above a certain batch size) is always the same amount if you don’t care about speed. Or maybe some compounds react to heat in a way that helps the recipe, but become more resistant when in large clumps.
I’m not sure how many of these actually are a thing, but I can think of plenty of “what if” scenarios that may cause ingredients to not be important or actively detrimental above certain levels.
While your statement on proportionality is true in a general sense for cooking Jragon, once you get past merely doubling a recipe, you start running into a lot of exceptions.
Two of import when scaling up more than one doubling are leaveners and liquids.
As Ethilirist pointed out, yeast used for brewing doesn’t, the same holds true for applications in baked goods ( Chemical leaveners as well).
Liquid for rice does not scale linearly, nor the liquid proportions for sauces and soups.
When taking a home recipe to scale up for a commercial kitchen, a prototype recipe can go through a lot of trial and error evolution even with pros before resulting in an acceptable product.
The only time you would not see linear scaling is when the ingredient is a catalyst as is the case in some molecular gastronomy, if the ingredient is living like yeast and so it self replicates, or it is a surface addition such as icing on a cake or salt on some meats and cheeses for example.
The reason why this is is simply a mater of proportions, with the exceptions mentioned above. So think of it as not mattering if you cook 2 x 6 inch round cakes 1 inch thick, or 1 6 inch round cake 2 inches thick. If pound cake is preferable: 1 pound cake needs 1 pound of flour, 1 pound of butter, and 1 pound of sugar. That goes in 1 pan, want 2 pound cakes? 2 pounds of each, then split into 2 pans or make 1 double sized one.
For jam, the link explains why doubling the size of the batch won’t work (because evaporating the water is an important part of the process). Even there, they don’t give a different recipe for a double-size batch. They just say to make two regular batches, which will of course require twice as much of every ingredient.
Almost every ingredient you add, if you need twice as much, you have to add twice as much. Any time OldGuy’s explanation doesn’t work, there’s going to be some specific reason why it fails. For yeast, you can use less because yeast is a living organism, and will reproduce, creating more yeast. For spices, I don’t know. I’d expect that those would need to be doubled, but maybe cooking time increases, and more of the seasoning comes out of the spice.
Do you have a cite for this in terms of leavening agents in baked goods? All the bakers percentage recipes I’ve seen don’t have any note about scaling up or down based on size. You can get away with less yeast, of course, but at the expense of longer rise time.
It depends if they are decompositional leaveners or living. Decompositional (like baking powder or soda) require more product linearly with volume, Living simply require more time or more of a start.
Well, yes, but you can scale up a living starter, so far as I know, to no detriment to the product and keep the times about the same. I generally ballpark the yeast for doughs for this reason, but I make sure to keep hydration (flour-to-water) scaled linearly.
Situations where scaling may not be linear are if anything is entering or exiting the system from the environment (e.g. atmospheric moisture or steam, respectively), or if interactions with the cooking surface are relevant. In these cases, exposed food-air surface area and food-container contact surface area play a role, and those don’t necessarily double if you double the recipe.
Also, heat transfer often doesn’t always work the same when scaling.
This is not something I ever really deal with in the kitchen, although other posters have listed some examples. It’s common in the lab. Once upon a time I ran many reactions in 1 dram vials at room temperature without any trouble. I scaled this up once and ended up with a substantial exotherm that decomposed my catalyst and some of my product.
Here’s a cite: I have a copy of The I Hate To Cook Book by Peg Bracken (recommended for confirmed old bachelors who either can’t fry water or can’t be arsed to, like me), which is full of (relatively) quickie streamlined recipes.
Somewhere therein, I recall, she mentions that ingredients (salt in particular) don’t scale when doubling a recipe. The recommended procedure to double a recipe is to multiply the salt by 1.5 (IIRC) then taste and adjust as needed.
That makes absolutely no sense to me. Like I said, my sausage recipes are all based on weight, and to get them to taste right, salt has to be about 2% by weight-to-mean, no matter the size of the batch. I’ve made small batches, I’ve made big batches. The salt levels have always scaled exactly, and when you find sausage recipes, you’ll often see them expressed in these sorts of proportions.
As to why that makes no sense, think about it. If you make 5 batches of stew with all the same proportions and mix them together, why would the salinity be any different than one big batch of stew made with 5x the salt? The only possibility I see is evaporation of liquid, but that should make the smaller batch saltier, not less salty, than the bigger batch. (And in something like big batches of sausage, it would make no difference whatsoever.)
This is one of the problems I run into at my current job, cooking at a retirement home. We’ve got some corporate yahoo who “designs” the menu by searching the Internet for recipes and telling us, “cook this neato recipe!” Except the recipes she’s finding are all designed to serve 4-6 people (seriously, these recipes are all coming from a “reader-submitted” recipe site). I have to make them to serve 150. (Aside from the scaling issues, there is also the time issue. “30 minutes prep time”? Yeah, if you’re cooking it for 4 people.)
Fortunately, with my 30 years of professional experience, I’m the least-experienced cook in the kitchen, and all three of us cooks have extensive experience in “volume” cooking. So half the time we ignore the recipe and use our experience to prepare a comparable dish.
Too late. I baked it. I baked it before I saw your note to not attempt. Now it is in the pan, smelling of the charred remains of a thousand guilty witches and pulsating with the steady, labored rhythm of a cancer riddled black lung. What do I do with it?
Yeast growth is exponential (or resembles an exponential curve) as long as there is sufficient nutrient and favourable conditions, so if you use half the yeast (or double everything else), you do have to wait longer, but not twice as long.
