# Stockpot size required - formula to calculate

Is there a formula for working out the pot size required for specified bone weight and water volume?

For example, I would like to make beef stock using 5kg of bones and 5 litres of water, what pot size do I need?

Bones are somewhat more dense than water, but you can just take the density as 1 kg/L as an approximation. That means 10 L of water+bones. It's easiest to avoid splashing if you only fill your pot to about 3/4 full, so that's about a 12 L pot required.

As Sneftel says, you'll have about 10l*.

With stock simmering very gently you can go really quite close to the top. I'd use a 10l pot because I have one but also they're easily available. Put the bones and any veg in first then fill to say 5cm from the top if starting from cold to allow for thermal expansion. I'd simmer with it full to 2cm from the top. Top up water as required. Even with a lid (which you should be using for long simmers) some evaporation will occur, so starting with 5l doesn't mean finishing with 5l unless you top up.

* Beef bone has a density of about 1.4 g/cm³, meaning that 5kg of bone only takes up 3.6 litres. But that assumes the bones fill with water and lack marrow, also that you don't add any veg.

• In fact, I'd fill a little less than that until I see how much it rises. That close to the top I'd probably still put a screen or the like over it to make sure it doesn't splash too much when it bubbles. May 4, 2023 at 19:05
• @KeithDavies I do have a splash screen, but the thing to use here is the lid. May 5, 2023 at 12:06
• for some reason I imagined you described simmering with no lid, dunno why. I use a lid while simmering, a screen when reducing (by which time I've normally removed the material I'm making stock from, which brings the stock level way down also). May 6, 2023 at 15:58

Assuming you are looking to purchase a stockpot, my advice is to buy the biggest (and best quality) you can afford (plus conveniently handle, store, etc.) You will never regret having a big, high quality pot. I bought a restaurant brand 22-quart [22 US quarts is ~20.8 litres] a few years ago, and love it.

• You may regret having to store something so big. I have 5l and 10l stockpots (used mainly for making soup and paneer - when I make stock it's in the slow cooker). One fits inside the other for storage and I can lift the pair down from the top shelf. Twice as big again will take up a lot of room May 5, 2023 at 12:03
• I agree with you, that a single pot as large as you can handle/store is a very good answer to many questions including making stock. However I think it is important to make sure it will fit all the requirements you have for a large pot. For me that includes making stews, being able to go in the oven for large casseroles and also work as a fermentation vessel. May 6, 2023 at 8:11
• I'll add that you want to make sure you get the biggest one that will fit on your stove top, for example, my 40qt stock pot is too big for a normal stove and requires a special oversize (200k btu) propane burner to properly boil water in it. May 22, 2023 at 3:47