I find that gluten-free pasta can taste pretty good, but I also have found that gluten-free pasta is sticky and loves to clump together. I took a dive into the science of sticky pasta, and here’s what I learned.
Gluten-free pasta is sticky and clumps together because it lacks the layer of gluten that wheat pasta has to entrap starch molecules. The high cooking temperatures cause the starch granules in the pasta to burst, releasing starch molecules and causing the pasta to stick together.
The high starch content of gluten-free pasta also makes the pasta hard and brittle when it cools down. There are some steps you can take keep gluten-free pasta from sticking.
The Science of Sticky Gluten-Free Pasta and Starch
Gluten is key for adding structure to food, so removing gluten from food means something else has to provide structure. Gluten-free foods, including pasta, rely more on starch, and on different types of starches, for structure.
As gluten-free pasta is heated in water, the starch granules start to become less rigid and absorb water, making them expand. The starch granules eventually burst after they’ve absorbed too much water, releasing starch molecules into the water and making the pasta sticky.
These burst starch granules and released starch molecules can become entwined with the starch in other pieces of pasta that have also had their starch granules burst and released starch molecules, causing the pasta to clump together.
Fun Fact: When you overcook pasta it will become more sticky because the longer you leave the pasta exposed to heat the more starch granules will burst
This is not to say that wheat pastas don’t contain starch, because they are high in starch. The starch granules in wheat pasta also absorb water, but the presence of gluten reduces stickiness.
Comparing the ingredients of wheat-containing Barilla brand pasta to gluten-free Barilla brand pasta, the wheat containing pasta is made of semolina (wheat) and durum wheat flour, while the gluten-free pasta is made from corn flour, rice flour, and mono and diglycerides (emulsifiers that help oil and water blend).
While wheat pasta gets its starch from wheat, gluten-free pasta is gets its starch from corn and rice. Interestingly, starch from wheat bursts at a lower temperature than starch from both corn and rice.
This means that if wheat didn’t contain gluten, wheat pasta would actually be stickier than gluten-free pasta that is made of corn and rice because the starch granules in the wheat pasta would start bursting sooner during the cooking process and have more time to burst.
The only thing preventing wheat pasta from being as sticky or stickier than gluten-free pasta is a layer of gluten than forms around the wheat pasta during production. Starch molecules in pasta with this gluten layer aren’t able to be released into the water and become entwined with starch molecules from the other pieces of pasta.
Scientists have even looked at cooked wheat pasta and cooked gluten-free pasta with a scanning electron microscope, and the layer of gluten is visible on the wheat pasta. I never though there would be a day when we would be looking at gluten-free pasta with a scanning electron microscope, but here we are.
Why does Gluten-Free Pasta Become Hard and Brittle when Cold?
Gluten-Free pasta becomes hard and brittle because the starch granules in the pasta crystalize and become rigid when cooled. Pasta with gluten is not as hard or brittle because the gluten provides elasticity to the pasta.
Gluten provides both structure and elasticity to foods. We can imagine a pizza maker tossing, spinning, and stretching pizza dough that contains gluten, but if we tried to do that with gluten-free pizza dough it would fall apart because the dough wouldn’t be stretchy. (Also gluten-free pizza dough is expensive, and I do not toss around expensive things.)
When gluten-free pasta is boiled in water, the starch granules in the pasta begin to soften and become less rigid. While the pasta remains warm, the starch granules will remain flexible and the pasta will soft and bendable.
As the starch in the pasta cools it starts to harden into a rigid crystalline structure. This starch cooling and hardening process is also what causes bread to go stale.
Pasta with gluten also undergoes this same starch cooling process, but even after the starch has cooled and become rigid, the gluten allows the pasta to remain flexible and soft. Gluten-free pasta only has starch to provide structure, so it remains hard and brittle when cold.
5 Tips and Tricks for Reheating Gluten-Free Pasta
Reheating gluten-free pasta can be a challenge, and it usually wont be as good as when it was freshly cooked. Here are a few methods you can use to reheat your pasta. You may have to try different methods depending on the brand on pasta you’re using.
- Refrigerate your leftover pasta mixed with the sauce
Storing your leftover pasta mixed with the sauce will allow the pasta to absorb the liquid from the sauce, which will prevent it from being as hard and brittle when you reheat the sauce.
- When microwaving your pasta with sauce, make sure all of the pasta is covered in sauce
Whether or not you stored you pasta with sauce, make sure that every inch of every noodle is covered in sauce when you’re microwaving it. I generally don’t store leftover gluten-free pasta in sauce, but I get decent results when adding sauce and then microwaving it. I’ve found that if I don’t thoroughly mix the sauce into the pasta, the parts of the pasta left uncovered don’t soften as much and remain harder to chew.
- Cover your pasta while microwaving it
Covering your pasta will trap in the heat and moisture while it reheats. You could cover you pasta with a wet paper towel, or some food storage containers have small vent holes in the lid that you can open, allowing the lid to be left on while in the microwave.
- Microwave the pasta for a long time
I’ve had decent results reheating gluten-free pasta in the microwave, but it always takes longer that what I think would be necessary. I’ve found that a serving of gluten-free pasta mixed with sauce can take up to 5 minutes in the microwave to be fully softened.
- Reheat your pasta by adding hot water
If you didn’t store your pasta mixed with the sauce and you don’t want to microwave it, you can add the pasta to hot water for a few minutes to soften it.
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