Why are potions always brewed in extreme bulk?

Question

This isn't a question intended for any specific setting. Rather, this is a general point of curiosity that occurred to me while brainstorming my story. Potion brewing is almost inexorably tied to the image of a cauldron. Whether it be witches standing over a cauldron big enough to boil someone alive in and stirring it with a big stick, or more reasonably-sized personal cauldrons in, say, Harry Potter, potions are very, very frequently being brewed in these bulky, thick metal pots, to the point that some people don't realize they ever historically saw mundane use.

The thing is... cauldrons are big. Even the small ones for personal use, as far as I can tell, can hold a lot of liquid. Even if we assume half a liter, about the size of a commercial water bottle you'd find for sale at a deli or pizza place, is an appropriate serving size of the average potion, then even tiny cauldrons, when filled with potion ingredients, would make at least a dozen servings of such a thing. And yet in, say, Harry Potter, we're told that on Harry's first day of potions class in the sixth book, Professor Slughorn had a "large, bubbling cauldron" of Felix Felicis on display for the class... a potion where a single serving size looks like this:

The unspoken implication is crystal clear: any world where cauldrons are heavily associated with potion-making is a world where potions are almost always brewed in bulk. Where dozens, maybe even hundreds of servings of a single potion are brewed at a time.

What might the reason be that brewing potions in extreme bulk is such a natural and widespread form of potion-making that cauldrons could possibly become so heavily associated with it?

Answer 1

Exact Proportions.

The ingredient ratios in a potion must be very precise. The easiest way to achieve this is to brew a large amount.

Suppose you need 1 litre of swamp water, 10 grams of ant juice and 0.5 grams of butterfly testicle powder, and can reliably measure anything up to the closest half gram. Then due to measuring errors you will end up with anywhere from 0 to 1 grams of butterfly testicle powder. In particularly you might use double the correct amount and ruin the potion.

If instead you brew 100 litres of potion, then you need 50 grams of powder, and the error is only between 49.5 to 50.5. So you have at most a 1% error.

This also applies when creating butterfly testicle powder in the first place. The potency varies between butterflies. So if you only need 1 butterfly's worth and I only need 1 butterfly's worth, and we each grind up one butterfly, then we might end up with different potency and cannot trade recipes. Better everyone in the area pools their butterflies. Then the resulting brew is measured for potency and redistributed.

Answer 2

For the same reason that to mine precious metals or stones you need to process a lot of ore: dilution.

If potion making was just a matter of mixing the right ingredients, any wannabe mage would just need to start mixing and experimenting.

The real deal instead is mixing the right ingredients and then concentrating them: you start with a cauldron and when you are done with the concentration you end up with a couple of vials.

Answer 3

A good potion is, literally, the "cream of the crop".

The actual magic potion separates out on top of the rest of the liquid, like oil floating on water, and makes up less than 5% of the end result of your brewing.

Just like with separating cream (3.5%) from milk, the final step is to carefully skim off the potion, leaving the (potentially toxic) residue behind. This final step also contributes to the quality of the potion, and the skill of the potioneer — leaving potion in the cauldron is an expensive waste of materials, and leads to smaller batches, while diluting it with the dross will weaken its efficacy.

A professional potioneer, of course, has an easier time of it than a home-brew; larger batches mean a thicker layer of potion to skim off, for higher quality potions — and any left in the cauldron is a lower proportion of ingredients, making it less wasteful.

Answer 4

One of the ingredients comes in discrete units.

Think of making cake batter. I need two cups flour, one cup sugar, one egg. I can't make half a recipe, because I can't halve an egg, or if I do, I'm throwing half an egg away for no reason. As long as flour and sugar are relatively cheap compared to eggs, I might as well make an entire batch, even if I don't intend to use it all.

If eggs were very rare and expensive, like a key potion ingredient very well may be, you might as well make a full recipe, or even be required to if your rare ingredient isn't divisible at all (e.g. one whole newt, one princess's little finger, etc).

Answer 5

1. Economy of scale, same reason that making dinner for six people isn't six times as much work as dinner for one. If potions don't have a short shelf-life if properly stored (supported by the frequency of finding perfectly good potions in places that have been abandoned for centuries), then it makes sense to make big batches, especially if you are either selling them, or using them frequently.

2. There is a final step to making a potion that is very tricky and has a high failure rate. If you are able to get it right only 1% of the time, you need a big batch of "potion base" to ensure success.

3. Actually, the concept of "potion base" brings up another possibility- maybe there are only a few basic types of potion bases, with the specific differences coming from later ingredients. If you can make many different potions starting with the same base, it makes sense to make a lot of it.

4. Ingredients are very potent, and need to be highly diluted to avoid toxic side-effects.

5. Outside factors. If you need a weekly dose of Immortality potion, but it can only be made during a solar eclipse, you need to plan ahead. Perhaps a necessary ingredient will spoil quickly if not used right away, or you need a large iron vessel to focus the magical energies involved. Or it's great-great-great grandma's recipe, and if you don't it right, she'll come and haunt you and you'll never hear the end of it.

Answer 6

Perpetual stew.

https://en.wikipedia.org/wiki/Perpetual_stew

A perpetual stew, also known as hunter's pot[1][2] or hunter's stew, is a pot into which whatever one can find is placed and cooked. The pot is never or rarely emptied all the way, and ingredients and liquid are replenished as necessary.[1][3] The concept is often a common element in descriptions of medieval inns. Foods prepared in a perpetual stew have been described as being flavorful due to the manner in which the ingredients blend together,[4] in which the flavor may improve with age...

The cauldron is never emptied. Potions from before are included in the potion being made. Thus potions grade into one another, each with magical flavors reflecting the heredity of the perpetual stew that resides in this cauldron.

One might seek out a certain cauldron and its occupant for making a certain potion. The cauldrons are each very different from one another, as one might expect.

Answer 7

Sorry to Burst Your Bubbl(ing Cauldron)!

The fact of the matter is: there is no sensible reason to brew potions in extreme bulk, except as a potions master preparing stock for sale or distribution. Mostly, the muggle notion that cauldrons are always big black iron pots comes from cartoons and modern kiddie literature.

Cauldrons have historically come in a wide variety of sizes, shapes and materials. Iron is common, but equally common are brass, bronze and copper. And of course, there are also cauldrons of alumina, steel, clay and silicon carbide for more refined alchemical & potions work.

Here are some nice brand spanking new iron cauldrons in a variety of sizes:

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And some various sized & well loved older vessels:

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Here are several smaller cauldrons from the Author's collection. Note the #4 aluminium cauldron in the upper left (with the lid), the #3 iron just below and the #2 iron over towards the right. Various other necessaries for brewing up small potions are also shown.

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The reality is that one uses the size cauldron appropriate for the amount of whatever potion or concoction one needs.

Since you mention the Wizarding World specifically, I'd only note that JKR herself is perpetuating the myth of the huge witches cauldron. There is in fact a collection of her sketches, and we can clearly see the ignorance! (She draws very well, by the way. I'd've liked it if the books had more of her illustrations in them!)

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At the other end of the spectrum, sometimes even the muggles don't realise how truly gargantuan certain potion making operations are and how very pantagruellian the cauldrons must be!

Answer 8

Simple economics.

Lets say it takes 2 hours to go through all the motions of brewing a potions. Lets say it also takes 2 hours to brew a cauldron of the stuff since you dont have to cut some portion of mandrake root to make sure you dont exceed the required amount but you also take more time like grinding all the butterfly testicles*.

So why wouldnt you? Its just smarter that way, and almost every brewbook will only list bulk ingredients anyway. Add Daron's explanation and you are golden.

*thanks Daron its just too good not to use butterfly testicles in potion ingredients. It adds so much to the flavor.

Answer 9

One reason things are done in bulk is surface area to volume ratio is lower which can help a number of things. In real life this is one reason why certain smelting processes are done on a very large scale: because it increases energy efficiency when heating the product because it requires so much heat to begin with. I'm sure you could cook up something else that dissipates the brew through surface area which is required to maintain potency until the reaction is complete.

Answer 10

You could redesign potion recipes for the modern world with glassware and normal equipment, but it would be a huge effort involving a lot of experimentation, death, and money.

Easier to stick with what works.

In terms of size, you generally need to purify the potion at the end for specialized things like Felix. You collect the drops of liquid gold for the potion. A larger size allows the extremely toxic and volatile substances within more room to not explode.

Answer 11

What happens in the cauldron is the manufacturing process, not the end product.

Similar to many modern manufacturing methods, the vast majority of what your brewing process creates is - waste. You need to make a large batch to get a few potions out.

Water, especially, is likely to be the main ingredient in your potion. If you google around a bit you will find the surprising amount of water that some common items require in their manufacturing process. Why would potions be so different?

Answer 12

All potions are created equal, but some are more equal than others.

Resistors are electrical components that have a number of colored bands on them. The last band is the tolerance of the resistor; essentially, how close it's going to be to the labeled resistance. Some are guaranteed to be within 10%, some within 5%, some within 2%, and some within 1%

When manufacturers make resistors, unless making them for a specific known target, they often won't have a separate process for making the 5% resistors from the 10% resistors. They'll just make a whole bunch of resistors, test them, and the ones that are within 5% get the gold band, the ones that are 5-10% get the 10% silver band.

It's the same with Potions. You could put in a lot of time and effort and get the high quality ingredients, and the exact stir time and the cook time to get a perfect, high quality potion, but you don't have to.

If you cook up a huge batch of healing potions, and decant them into bottles, and test them, you might find that:

• 60% of the resulting potions will be good enough for first-aid-level cuts and scrapes, or small maladies.
• 25% Are good enough for things that you might want to schedule a doctor's appointment for. Ingrown toenails. Ear infections. Persistent coughs.
• 10% might be good enough for injuries that might require Urgent Care assistance. That wound needs stitches, and possibly prescription antibiotics.
• 4% might be good enough for things that would require the Emergency room. Broken bones. Severe bleeding. Insulin shock.
• 1% are good enough to do RPG Combat Healing. Significant, un-staunched damage to limbs or vital organs. Need to be capable of normal function quickly enough to participate in ongoing combat situation.

And there's a market for all of them.

Answer 13

The actual potion is a tiny part of a huge cauldron. It's the little shimmering layer on top.... the residue when 99.9% is allowed to dissipate..... The sparkling bubbles as they escape at the surface.....

The rest of the cauldron is thrown away or used for other less wondrous things.

Answer 14

A huge cauldron doesn't necessarily mean dozens of potions. In a world with real witches, a cauldron's-worth of ingredients might render a single small vial of potion. How? Well:

• a) Duh... magic! Maybe when the witch tips the cauldron into a vial, the whole cauldron of stuff empties neatly into the vial (if the witch is careful, and I'm going to say that potion-brewing is not for the careless) and only a single drop is left to season the cauldron for the next concoction.

• b) Perhaps collecting the stuff into a pot creates the magic, but only enough for one serving and the rest you may as well discard or make into a stew. The first scoop out of the pot is the potion, the rest is not, even though it's the same stuff. If you want ANOTHER invisibility potion -- sorry, you have to put an unused troll brain into a pot combined with another batch of ingredients. The magic from that last brain was suffused into that potion you already made, and that's all you get from one troll brain.

• c) Gazing into a magical cauldron allows a witch to see the future or a distant place in some fiction. Maybe the cauldron doesn't produce potions at all, or perhaps a wise witch brews a huge pot because of the knock-on effects, although the big mixture still produces only a single (or a few) dose(s). Personally, I relate cauldrons with scrying moreso than potion-making.

• d) Maybe it's the beginnings of a reduction, just like in cooking and chemistry (boiling off water and other stuff to render a small concentrate).

• e) Maybe after mixing the huge pot, you dip a particular rat bone into the pot, burn it, stir the ash into chokecherry wine, and that's your potion. Dip another bone, or dilute the ash into several cups of wine and the potion works not at all. It ain't chemistry, it's magic.

• f) Or maybe they're making dozens of potions at once, which makes the usual economic sense. You have to either kill a troll, or hire someone to kill a troll, or steal from someone who is capable of killing a troll (or capable of hiring someone to kill a troll maybe too far with the troll thing?) to get a troll brain (or whatever horrible ingredient you need). When you're dealing with bizarre, rare, and often seriously-dangerous-to-acquire ingredients, you gotta stretch that stuff as far as it will stretch. I imagine a witch would need servants and associates to acquire ingredients, and would conjure or retain them through foul means and/or seductive rewards.

Answer 15

Real world example: Rose Oil

Please read these two articles https://en.wikipedia.org/wiki/Rose_oil and https://archive.org/details/b28059979/page/n299/mode/2up

To make Rose Oil you need a specific flower harvested at a specific time of year and a specific part of day (just before sunrise) to get a worthy ingredient.

Then you start processing it by boiling with a lot of water and distill it repeatedly. Even with a long and polished process you get an extract of only about 1:3000 (yes, just one of three thousand) of the flowers (not counting the spent water, fire, etc.) which is supposed to be able help allergies, if it comes into contact with the skin. After some more processing and dissolving there is some refined product, which (while wonderful) is not even magical.

The process has been basically the same for hundreds of years. And yes, the rest of used ingredients are just trash after the extraction, and not good for anything, maybe compost. All that matters is the 1:3000 part of roses, the rest is just totally wasted.

A lot of people work on getting some reasonable results from the harvest, as it can be done only once a year and the the field cannot be used for anything other.

Magic world discussion

Typical magic potion is done from a lot of special ingredients, usually by single witch, living far from people (for many reasons such as their safety, her safety, the waste she makes (and that is probably not only terrible, but also toxic and maybe even cursed), secrecy of her recipes, good place for harvesting, ...)

The recipe will probably will require some refined oils and other extracts (and not just one, but say 3-5-7-9 or something like that, depending on final product) — in specific combination, and used under specific circumstances, like under full moon (both for its magical effects and polarised light) and some others — to extract the real magic from very specific ingredients. And yes, those extracts have to be undiluted and they are wasted after the use.

But the result is real magic potion with specific effects.

Now, while the final extraction yields one small vial from like 5 liters of extract and a few really rare ingredients (say optimistically just 1:100 rate), and takes just few hours.

But try to count, how many specific flowers, mushrooms, roots etc. had a single person to harvest, and that probably each of the extracts is based on some other ingredients, which have to be harvested at another time of year in insane quantity and processed by a really long procedure.

No wonder, that nearly all the time there is a big cauldron, in which is something boiling. And that the real treasure (some bottles of different extracts placed in some convenient place, say in cellar, where is more consistent cold and humidity) is not visible to unknowing eyes, with the cauldron on display and flowers, roots, branches, mushrooms are drying everywhere possible.

The witch does not know what she will need after a half, one or two years, but she knows that it would take some insane time to process all those ingredients and that it could not be done in a few days, as some things are ripe in summer, some in winter, some under the full moon without clouds, others on stormy nights with a new moon etc. etc.

And with witchery, instead of modern chemistry, she is not really sure, what is necessary and what is just optional — she knows what worked for her grandma, she may have discovered something herself, but when there is always life at stake, there is just so much you can try to change in one step (and probably just lose a lot of Rose Oil and other extracts, so it would be really expensive, even if nobody dies from that).

So she'd rather stick to the rules and add one young living newt from the swamp, while maybe there are just needed some impurities from that swamp mud, which also contains some sulphur and arsenic in balanced amounts. Just how she could be sure, when there is working recipe and some lore, that it one time worked this way and so everybody in her family do it this way as precisely as possible.

Moreover as she processes all kind of dangerous, boiling, flammable and toxic substances, no wonder that her usual clothes are in a terrible state (they were new long ago, but if you know that nearly every time you work you damage them somehow, then you really do not use new clothes for work) and why she looks like she looks when regularly in contact with all kind of allergens, toxins, acids and such.

And it is also one more reason, why final extractions are done far away from human eyes — not only for tradition and protection of her secret recipes and avoiding risk, that somebody would like to see what she does and then accidentally knock her equipment down, resulting in total loss of much work and his life — but also that she does it usually naked or at least underdressed — yes tradition too, but also there is too big a risk that something from her clothes may fall into the mixture and destroy it totally.

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So I always believed that potion making witches do a lot of work at the time they can and save a lot of extracts for those final mixtures somewhere hidden to be able use them in reasonable time, when they need some specific potion. And, as they also supply last resort healers for many villages around, that they have a relatively big haul of half-made healing potions ready, usually just boiling in the cauldron, as they can expect that somebody will come soon with some problem and then they could just take part of that base, add specific drugs and make some "medicine" in a relatively short time at the cost of the "medicine" expiring in days or max weeks and being unwieldy, but sufficient for "simple" healing now and here in time of days — while real potions which would save you in a dungeon after years of waiting are much more concentrated and expensive and harder to make.

On the other hand if they want their privacy until their help is really needed (and then add a big part of placebo, as it works too), they keep some strange looking things around, which are not threading them (bones in cauldron, strange colored things of unknown origin, but after distillation totally useless and mainly inert and such) but are quite impressive to the customer.

And if all work is done and nobody comes, well good broth with vegetables and mushrooms could be eaten as well instead of using it for diluting the real weak healing potion :)

You know, why they add a lot of something to the cauldron, when someone comes and asks for medicine — if there is just strong soup, it is good to use it as carrier for the real thing and make sure, that customer is not able to drink a week's worth of active substances (which he would do for sure, if just given small vial and told how many drops daily, but if it is one full spoon morning, one evening and say this long prayer before and after, the risk of overdosing is way smaller).

Answer 16

Potions are potent, and this comes from concentrating them. The whole bubbling for hours thing is just to reduce the liquid so that you can get a useful dose in one gulp. Felix felicis would make no one happy if they had to drink four pints of it before seeing an effect.

Also, for most potions, after reducing as much as possible you just skim off the top scum, which is where the active ingredients get concentrated.

Answer 17

Maybe one of the ingredients is the meat of a large, rare, possibly dangerous animal, let's say a buffalo for now, but it could be anything from an elephant to a tiger to a dragon, etc.

Sure, you could just use part of the buffalo and make small batches, but then the rest of the buffalo would rot and spoil, and that's just wasteful, and then every time you want to make a new batch, you have to go out and capture and slaughter a new buffalo, most of which won't get used and just go to rot again? No thanks.

It's just much more economical to use the entire buffalo and make a large batch. The finished product, once properly bottled and sealed, will last for a good long time, and you can sell them to anyone who wants. Maybe you only need to make a new batch every couple of months. (You can of course work on making other potions using different recipes in between, just to keep busy.)

Answer 18

Magic potions require a magic catalyst to "spark". And a magic catalyst is created by the witch brewing the potion using their personal mana, being a catalyst rather than a reactant they are not consumed by the sparking of the potion. However being magical and mana created rather than a normal physical catalyst they do evaporate once the reactants are consumed.

This means to spark a big cauldron of potion takes the same magic effort (not mundane effort of collecting the reactants) as a small cauldron.

For certain basic potions it is possible to continually supply reactants, and remove sparked potion on an industrial scale so that a single catalyst can run indefinitely, however more complicated potions don't tend to work well under these conditions, the reactants need to be evenly mixed or else the catalyst will fade.

Answer 19

The big cauldrons you see everywhere isn't aren't for brewing potions, they are for flying around in.

Unfortunately, preparing a cauldron for flight takes a lot of work and time and boiling various noxious liquids in it.

Answer 20

You can do it only once. The recipe is copyrighted by demonic entity and it demands a specific part of your soul as a royalty. You can resell the final product, or obtain a teacher licence suitable for spreading the heresy to your students.

Answer 21

To prevent (too much) contamination.

Since the enchantments seep into the cauldron, to ensure that you have a potion that mostly does what you want, you must make so much that the other effects from contamination become minimal.

Answer 22

Stratification.

You add all these rare and expensive ingredients, however, you really do not need "eye of newt." What you really need is the extremely rare organic compounds that then then interact with the inorganic salts of the other ingredients. you then need to bring the concoction to the right temperature to allow the chemicals interact properly, boil off some volatiles and precipitate out useless waste matter, such as the fleshy parts of the eye that do nothing for the mixture.

You then skim off the scum and what ever layers you do not need to get to the real stuff. You then syphon off that fluid, to seperate it from the rest of the mixture.