Many people store ketchup and mayonnaise "upside down", thinking that it will be easier to pour out later, but in fact, putting ketchup upside down can cause problems. Based on experience, Japanese professional cook Aimi Uematsu explains the key differences in the preservation methods of the two.

Mayonnaise can be stored upside down, but ketchup must not be like this

Although mayonnaise and ketchup are both stored in similar tube containers, there are key differences in the way they are stored. Mayonnaise can be put upside down without any problem, but ketchup is "NG" when put upside down. The reason is that ketchup is not in an emulsified state, but is just a mixture of ingredients. If the bottle is turned upside down, the liquid components inside will sink due to gravity, causing the water to seep downwards, and may even seep out from the gaps in the bottle cap.

Mayonnaise is "emulsified" and will not separate as long as it is not exposed to extreme high or low temperatures, so it can be stored upside down.

Therefore, opened tomato sauce should be placed with the cap facing up. Most manufacturers also clearly state on their official websites: "Please keep the bottle cap upward when storing."

Do you want to vent the air? Key differences in preservation

Another common question is: Should the air in the hose be squeezed out after opening?

For tomato sauce, the answer is "it must be drained." Because if the air is left in, the moisture will be easier to separate; and after the air is discharged, the phenomenon of stratification and leakage can be effectively reduced.

As for mayonnaise, both methods are possible, but if you do not empty it, leave air in the bottle and store it upside down, it will make it easier to squeeze out the remaining content and use the last drop.

Use it wisely until every drop is left

Whether it’s mayonnaise or ketchup, it’s always frustrating to use the last bit.

Mayonnaise can be placed upside down to leave air for easy access; but tomato sauce is not suitable for upside down use. Uematsu recommends that when using it, you can first open the bottle cap to let a small amount of air in, then close the bottle cap tightly, press the bottle mouth with your fingers, turn the bottle upside down and shake it gently up and down a few times, and the contents will be concentrated on the cap end, making it easier to squeeze out. Be sure to make sure the bottle cap is locked tightly during operation. If necessary, tape it to prevent it from exploding.

If there is really only a very small amount left, the easiest way is to cut open the bottle with scissors and scrape it out directly with a spoon.