Like everything, scaling up recipes to larger portions takes a little bit of practice. I was reminded of this while catering an appreciation event for about 40 local teachers. 

They wanted something comforting, and nothing says comfort quite like a hearty tomato soup. But scaling that simple recipe from a small batch to one big enough is where things can get interesting.

First thing, you need to remember was the importance of weight versus volume measurements. Standing there in the kitchen, staring at all those tomatoes, I knew that relying on cups just wouldn’t cut it. A cup of diced tomatoes can vary too much depending on how tightly you pack it. Instead, I went by weight—about 15 pounds of tomatoes. It was the only way to make sure I was getting the flavor just right, without the risk of under- or overdoing the key ingredient.

Scaling a tomato soup recipe.

Another challenge you’ll face is dealing with small quantities like spices. I remember standing in front of that big pot, teaspoon in hand, thinking, “Ten teaspoons of salt can’t be right, can it?” And it wasn’t. Spices don’t scale up evenly. A teaspoon of salt for four people doesn’t simply become ten teaspoons for forty… that would be a salty disaster. I scaled carefully and tasted as I went, especially with things like thyme and chili flakes. A little too much of either can overwhelm a pot of soup this size. I learned to start small and build up gradually. You can always add more. Removing seasonings is the problem. 

Know that when it comes to scaling recipes it’s usually alright to round to practical numbers. Nobody wants to be measuring out 17.8 ounces of tomatoes when you’re juggling multiple pots on a busy stove. I rounded to the nearest ounce, which made things a lot smoother when the heat was on.

And finally, save your notes with this tool. What worked, what didn’t. Save this information. Because when you get it right for forty people, you want to be able to do it again without starting from scratch.