Learn the science behind:
A rice pudding, isn’t that just a regular, simple dessert? Nothing special or fancy?
After making a rice pudding the other day (for testing The Turkish Cookbook), and of course, making several steps along the way, I thought the contrary: rice puddings are actually very interesting desserts. They’re rich and creamy, with pretty simple ingredients and showcase rice in a very different way than its more common savoury appearance (e.g. risotto).
At first, making a rice pudding seems quite simple. However, once you start entering the world of rice puddings you will realize there are hundreds, if not thousands of types of rice pudding. You will read whether or not you should wash and rinse your rice on forehand, whether you should grind the rice and what flavours go well with it. There’s more (science) to your regular ol’pudding.
What is a rice pudding?
For the sake of simplicity we call anything a rice pudding that is: “a sweet dish with rice as a main ingredient, generally cooked in a liquid that makes up the rest of the pudding”. A rice pudding can be made with whole rice kernels, ground down rice (as the recipe below), with all sorts of milk, with or without dairy and with all sorts of sweeteners and spices. You can travel the world trying out all sorts of different rice puddings!
Why to use rice in a pudding?
Rice, of course, has a major role to play in a rice pudding. Rice contributes some flavour, but really most of what it does, is determining texture. Rice is what thickens the pudding and ensures that your liquid milk (or cream or water) transforms into a creamy slightly solid consistency.
The rice does this thanks to an important component of the rice: starch. Starch is not unique to rice, there is plenty of it in potato, corn and wheat flour, to name just a few, as well. Even though all these foods contain starch, the types of starch differ per source. This is because starch is not just one molecule. It is a combination of molecules and by changing their sizes and ratios the properties of the final starch changes.
Starch in rice
Starch is not just one molecule, instead, it is made up of two different types of molecules: amylose & amylopectin. These two molecules and the ratio of the two in your rice, determine, to a large extent, how your rice pudding will turn out. These same molecules also determine whether your potato is a waxy or a starchy one.
Amylose & amylopectin are both long chains of glucose molecules. Glucose molecules are so called monosaccharides and belong to the carbohydrates. Amylose is a long linear chain of these glucose molecules, with only minor branched out portions. Amylopectin on the other hand is a highly branched molecule, meaning it has a lot of sub-branches coming out of the longer linear chain. The types of amylopectin and amylose present in your chosen rice, will greatly influence how well it forms your pudding. For instance, the amylose in starch is best at forming (heat stable) gels whereas amylopectin makes a stickier paste.
What happens when making rice pudding
When you make your rice pudding the starches undergo several transformations. An important property of starch is that it can absorb a lot of moisture. By heating the starches gently and placing them in water (or milk, for that matter) the starches will start swelling up and absorbing a lot of this water. At increased temperatures these swollen starches will break. This thickens the mixture further by freeing a lot of these moisture absorbing molecules. It is what thickens the pudding (similar to what happens when making a pie filling or bechamel sauce) and is called gelatinization.
Which rice to use in rice pudding?
Generally, a rice with a high amylose content will stay in tact easier and cook into dry separate rice kernels. A rice with a low amylose content though will be sticky after cooking. The amylose content tends to be anywhere in between 0 to about 30%.
The world of rice classifications is not a very clear and precise one (as we also noticed when discussing the science of a great risotto). Rice can be classified based on size (short, medium or long grained), based on its application (paella rice) or its breed (e.g. arborio) for instance. It does not give the amylose content on the packaging though. Instead, you should use the applications shown on the packaging as a guide. A sticky rice will likely be one with a low amylose content, whereas one used for a fried rice will tend to contain more amylose.
Returning to that question of which rice to use though: you can use just about any rice. The different types will just result in different types of rice pudding. If you’re looking for a stickier, variety, use one that’s low in amylose. If you prefer to taste the individual grains a bit better, take a high amylose one.
You can use the simple small recipe below to test you different rice varieties. We tested, amongst others, risotto vs basmati rice. They came out very different, but both tasted great and it just depends on your preference, or what you’re used to, which one is best for you!
Using parboiled rice
Generally, the advice seems to be not to use instant or other pre-cooked rices for rice pudding. It’s not really clear what the reason is for this (and whether everyone will actually agree with this), but it might have something to do with the retrogradation of starches.
Parboiled rice is made by pre-cooking the rice before bringing it to market. This way, the consumer only has to finish off the cooking of the rice. By parboiling the rice the starch is gelatinized already. During storage the starches molecules will again reorganize themselves and tighten up in a process called retrogradation. As you may have noticed when reheating some left over rice, this rice will be a little firmer than the original which is because of the retrogradation. Whereas you can still make rice pudding from parboiled (or left over) rice.
This same retrogradation process is also why a freshly made rice pudding will have a different texture than one a few days old. (Even though it’s still delicious if stored safely in the fridge.)
Grinding the rice
In the recipe we made (see bottom of article), we used a jasmine rice but ground the rice up. That way, the rice loses its structure and you end up with a smooth rice pudding. By breaking up the rice kernels, you also accelerate the leakage of amylose from the kernels. As a result, the whole pudding cooks more quickly.
Devon Cameron, Ya-Jane Wang, A better understanding of factors that affect the hardness and stickiness of long-grain rice, Cereal Chem, 82(2),: 113-119, DOI: 10.1094/CC-82-0113 ; if you really want to know how amylose and amylopectin impact rice puddings, this will be a good start, it’s not just the content of either one that matters, also their type and properties!
In Myoung Park, Ana Maria Ibáñez, Charles F. Shoemaker, Rice starch molecular size and its relationship with amulose content, Starch/Stärke, 59 (2007) 68-77, DOI 10.1002/star.20060056, link
S. M. H. Saif , Y. Lan & V. E. Sweat (2003) Gelatinization Properties of RiceFlour, International Journal of Food Properties, 6:3, 531-542, DOI: 10.1081/JFP-120021457, link
Kalidas Shetty, Gopinadhan Paliyath, Anthony Pometto, Robert E. Levin, Functional foods and biotechnology, 2008, CRC Press, chapter 3, link
Wikipedia, List of rice varieties, link ; showcasing just how many different ypes of rice there are, not just your general brown vs white rice for sure