Learn the science behind:
Ever had to scald milk for a recipe? This is when you have to bring the milk to the boil, and as soon as it boils you have to let it cool down again. Sounds useless at first sight doesn’t it? Why would you heat something up only to let it cool down again? A cinnamon roll recipe called for scalding milk and thus we needed to consider whether it was actually useful. In the end, scalding the milk does seem to do something, the cinnamon rolls turned out great (see for recipe at the end of the post).
The science of scaling sits in the milk, you wouldn’t see a recipe asking you to skim your water (and if you do, you’re bound to be fooled). But for milk it’s more common, part of it are historical reasons, but there’s also some decent science & chemistry behind scalding of milk.
What is scalding milk?
Whenever a recipe calls for scalding the milk it asks you to heat the milk, just to the boil and then cool it down again. In some cases you might have to cool it down to room temperature or even in the fridge, in others you can use it slightly warm. That will all depend on whether the other ingredients in your recipe can handle hot or warm milk.
In a yeast dough, as is the case for the cinnamon rolls at the bottom of this post, milk has to be cooled down quite a bit. If not, the hot milk will kill the yeast. So why bother at all with heating up the milk?
Using milk in a (yeast) dough
To be able to answer that question we have to zoom out a little more, why even bother to use milk in a bread recipe? Wouldn’t just water turn out fine as well? It’s true that cinnamon rolls, just like a lot of other breads, can well be made with water in stead of milk. However, using milk does have its benefits and most online cinnamon roll recipes do tend to use some sort of milk.
Since milk contains both sugars (lactose) and proteins it will make bread slightly sweeter, but also browner. Thanks to the presence of these sugars and especially proteins the Maillard reaction can take place at an accelerated rate. Apart from the colour and flavour, milk will impact the structure of a bread. Using milk tends to give a softer bread with a finer crumb, as we explained when discussing brioche breads.
A disadvantage though of these milk doughs is that they tend to rise slower and won’t gain as much volume as when using water. It’s mostly the proteins of milk that can interfere with these processes. Milk contains two main classes of proteins: casein proteins (essential for making cheese) and whey proteins. Whey are the proteins that are left behind after cheese making. Research has shown though that it’s mostly these whey proteins that can interfere with the dough.
When making a bread dough gluten development is essential. Gluten can form a network that can hold on to air inside the bread. During the mixing, kneading and rising process it is important that this gluten network can form properly. It is well known that, fats such as butter or olive oil, can prevent a proper network formation because of them coating the gluten. However, whey proteins can also interfere with the gluten. As a result, the presence of whey can lead to an increased proofing time as well as a smaller overall volume of the dough.
In order to get a milk bread with a proper rise and fluffiness, it would definitely help to take care of this whey protein interference. Whey proteins are sensitive to heart. Upon heating the whey proteins will denature and lose some of their efficacy. This is why some bread recipes will call for scalding the milk before adding it to the dough. This quick heat (scalding milk will never ask you to boil the milk for a long amount of time) will break down the whey. It should then make the dough lighter.
So even though it seems like a quite ridiculous step to do, it will actually help the cinnamon rolls.
Scalding in the older days
You might see scalding of milk turn up more in older recipes, even those where a gluten network is not important (e.g. muffins). This most likely stems from the fact that at the time milk wasn’t pasteurized, in other words, made safe for human consumption. So at the time people boiled their milk themselves before using it to destroy pathogens.
Cinnamon roll recipe & Another quick warning
Whenever you see a recipe where gluten development is important (e.g. other breads) and scalding of milk is instructed, it is probably worthwhile to do so. The recipe below asks for scalding the milk, of course. It’s not been testing without scalding the milk. The difference probably won’t be huge, but it sure sounds like it’s worth it.
However, when scalding of milk is done in a recipe without any gluten formation, think twice whether there’s a reason to do so, or whether it’s a historical artifact!
Now that you know that heating the milk is important a quick word of warning: the cooling part is just as important! When scalded milk is used in a yeast dough, you should assure it cools down properly. Yeast is a living micro organism and can be killed by heat. Adding yeast to hot milk will kill the yeast and as a result the bread won’t rise at all.
These apple caramel cinnamon rolls are heavily inspired by the ones from the Pioneer Woman.
Thinking about the apple and caramel?
Before you dig into these delicious cinnamon rolls. The apples in this recipe become super soft and juicy, just like they do in apple beignets! Also, curious to know what happens when making caramel? Or want to know more about cinnamon?
Baker’s assist had a note explaining the impact of whey on fluffiness of bread (article is no longer online available).
Want to understand more of the interference of when proteins with gluten networks? This research article explains it in more detail.