How does pâte à choux work?

…and when was it invented? asks reader Pat. The answer is that choux almost certainly wasn’t “invented” in the classic sense of the word. It evolved, probably through decades, maybe even centuries, of trial and error. The secret of choux is that it’s “double cooked”, a process that imbues it with some very special properties.

If you’ve made éclair or cream puff shells before, you probably recall the process. Water and butter are combined in a sauce pan and heated to the boil, at which point enough flour is added to turn the mixture into a fairly stiff paste. That paste is then cooked over low heat until it forms a ball, which is then finished by beating in several eggs, one after the other. It’s then piped and baked (the second “cooking”). Interesting. Curious. But what does it all mean?

Choux is a batter which by design contains a lot of activated gluten, and that’s unusual. Normally batters, regardless of how thick they are, are low-gluten affairs. Recall how one is time and again admonished not to stir a pancake batter for fear of toughening the cakes. The same goes for muffin batters, where agitation leads to big bubbles or “tunnels”, crowning and a gummy texture. That logic is reversed with choux, which is beaten vigorously in an attempt to activated the gluten and turn the entire thing into one giant bubble.

But then what does the double cooking accomplish? For one it causes the flour to gelatinize, which creates a starch mesh that helps reinforce the gluten. When baked, these dual networks help the bubble of expanding batter to stretch (they also help prevent steam from escaping). But the cooking also does something else. It partially denatures (i.e. damages) the gluten molecules so that they lose some of their elasticity, helping to ensure that when the single bubble is fully expanded it doesn’t snap back before the pastry hardens.

Amazing, n’est pas?

42 thoughts on “How does pâte à choux work?”

  1. How interesting. I see what you’re saying about the starch mesh and denatured gluten forming the right kind of network around the bubble of air, but where does that bubble come from in the first place? And why is there only one large one, instead of the usual structure of many small bubbles?

    1. The wetter the dough, the more the bubbles that are in it will combine together to form very large pockets. That’s why choux and popovers employ moisture-laden batters. All the extra moisture creates lots of steam which translates to big bubbles. Because the structure of the batter isn’t very strong (as in rigid), those bubbles will tend to combine with one another. But because the batter is very elastic, the bubbles that do remain will blow up larger and larger. The results are virtually hollow, steam-inflated goodies.

      1. Thanks! Sounds a lot like the same reasoning behind making bread with large holes.

  2. Cooking the choux well in the 1st step also allows for the proper amount of eggs to be beaten in.

  3. What effect does waiting for the batter to cool a bit before beating in the eggs versus beating the eggs in directly after adding in the flour have on the final product. Also, what difference does it make if you beat in the eggs by hand versus using a mixer? tx

    1. Hi Tracy! The main reason you don’t beat the eggs in right away is because you don’t want to risk cooking the eggs prematurely. As far as the difference between a mixer and beating by hand, there really isn’t much of one, though mixers always tend to be a little faster and deliver a more consistent end product. I rarely use a mixer for choux since I make in such small quantities.

  4. Hi Joe,my baker makes eclair shells that are crisp but the ones I make are quite soft. How can I make my shells a little more crisp? Thanks

    1. I think you just need to make sure they dry well in the oven. Once they’re bake, make sure to turn them over and vent them with a sharp knife so that the steam escapes, then leave them in the cooling oven with the door propped open slightly for at least half an hour. That should do it!

  5. Hi Joe! I tried making gougeres based on a recipe from a cookbook. It called for boiling a mixture of butter and milk in the first stage, then dumping all of the flour in at once. For the second stage, the batter was transferred to the mixing bowl to beat in the eggs, one at a time. Finally, I added the cheese and herbs. After baking them at 350F, however, they were flat, buttery disks that tasted prominently of eggs. I was hoping for a light, fluffy ball. Can you please shed some light on what went wrong? Was it the recipe, or the technique? Thank you!

    10 oz nonfat milk
    10 tbsp unsalted butter
    1 tsp salt
    1 c AP
    5 large eggs
    3/4 c gruyere
    1 tsp black pepper
    1 tbsp thyme

    1. Hi Rose! I’d be happy to help. But tell me first: were they totally flat and pancake-like? I were they hollow in the middle?

      1. Joe, They were totally flat and even concave when flipped over. Still had a little bit of air in the middle, though.

        1. Hmm…so virtually all the steam escaped from them. How long did you cook the dough…and did it leave a film on the insides of the pan?

          1. Since this was my first time making it, I followed the recipe to a tee and baked them for 25 minutes. I used a 1/2 sheet pan with a Silpat liner. I didn’t see any film, but this was perhaps due to the nature of the silicone liner.

          2. I meant when you were cooking the dough, right before you add the eggs. Sometimes it’s easy to shortcut that step, and it can have these sorts of consequences.

  6. Oh, I understand what you mean now. The recipe I followed told me not to add the eggs to the pan in which I made the paste of butter, flour, and milk, but rather once I transfer the aforementioned mixture to a mixing bowl to beat in the eggs one at a time. I did so with the flat paddle in my Kitchenaid at the lowest speed.

  7. I cooked the batter until all of the flour was saturated and the mixture was homogeneous.

  8. Hello! My eclairs come out really nice, I like making them. The only problem is that some of them are concave at the bottom, and the bottom is soft. Still others are noce and brown all over and have a convex hard bottom. Maybe I should make them bigger/thicker? Thanks!

    1. Hi Dima!

      It sounds like the heat might be a little uneven in your oven. Try rotating the pan once they’re mostly baked to make sure they dry evenly all the way around.

      – Joe

      1. Nope, it did not work. In fact, they fell flat the moment I opened the oven and did not rise ever since. They bake through well, the crust is nice and hard. But when they fall flat, the insides stick and they end up baking solid, with occasional cavity here and there.

        1. Drat! Now I’m starting to think your oven may be too low. That would explain the volume and underdone center problem. Have you calibrated your oven recently?

          – Joe

          1. Nope, I did not calibrate it. But I got the last batch right, by setting the temperature all the way to the max! I was so desperate and gosh, it worked!! They rose fine, and dried out before they could collapse.

            I guess one must eventually just experiment with their ovens a bit. Thanks for your input and answers, Joe, you are welcome to come and visit for some eclairs some time! 😉

          2. Wonderful news, Dima!

            Thanks for the report…and I may just!

            – Joe

  9. Hi Joe,
    I’m vegan. I’ve tried several egg replacers, including one I’ve developed and the results are always the same. They flatten, bubble a lot and turn hard. I’ve read you have to cook the dough until a film develops. I don’t think I do that. That is one possibility. Do you think bread flour would work better than all purpose flour? If you were to make a vegan eclair, what would be your choice of egg replacer?

    1. Hey Rocky!

      Cooking the dough in the pan until you get that film is key…it lets’ you know that the flour is gelatin and you’re getting that elastic mesh. I’d say try that first. As far as an egg replacer for this, you want something gooey so I’d go with a flax seed replacer and see what that does. It would be a serious coup if you you could figure out how to do this. I’ll want the recipe! 😉

      Good luck,

      – Joe

  10. How does all water, all milk, or a combination of both affect the outcome of a pate a choux recipe?

    1. Hello Charane!

      Milk tends to give choux puffs more color (due to the extra protein) and makes them a bit more tender. I generally prefer water since the rigidity makes them less likely to fall once they’re baked. But if you’re careful to crisp them fully in the oven milk can be a very good option.

      Let me know how they turn out!

      – Joe

  11. Made some choux this morning, but the batter was really thick even after I added the eggs. Where did I go wrong? I did measure out the ingredients according to recipie.

  12. Hi – how does the water content affect choux pastry? e.g. what would happen if I don’t add enough or if I add too much? Thank you!

    1. Hi Kimberly!

      The water (egg white) content of choux is actually crucial for getting a good puff. Too little and the puff won’t expand to its full potential. Too much is worse however because the batter becomes so slack that large bubbles can’t form. There’s a finger test in the batter post that will help ensure you get it just right.

      Let me know how it goes!

      – Joe

  13. Hi!
    if i need the elasticity of the dough.. why do i need to damages the gluten?
    i mean, we cook it because we want to develope the gluten.. so why the denatures help?
    hope u understand 🙂

    1. Hello!

      The damaged gluten is a side effect of the cooking process, which as I mentioned creates the gelatinized starch that helps the choux expand.

      Here in the States our gluten is very elastic, which means that when it’s stretched it wants to snap back to its original shape. A little denaturing helps prevent this contraction. That’s not necessarily the case in other parts of the world — like France — where gluten tends to be more plastic. In that case I expect denatured gluten is not a help. Does that make sense at all?

      Cheers and thanks for the question!

      – Joe

  14. Hi. My eclairs look perfect: golden all over and puffed up nicely. But the bottom is very thin. So much so that when I pipe in cream the bottom falls away. What am I doing wrong? (The whole eclair is cooked through and sturdy, no doughy bits, and dried out well.)

    1. Fascinating problem, Ella. Are you sure it’s just the bottoms? Or is the whole structure very thin? You may need a stronger flour to give them more rigidity. Just curious: are you using my recipe?

      – Joe

  15. Hi Joe

    At my work we make comte gougeres everyday, but we’ve been having so much trouble with consistency. Some batches once left over night go completely grey, or have multiple grey spots all through them. As far as i understand it this means that the flour is oxidising from not being cooked out enough?
    But we are also having problems of some batches going completely flat when cooked. We are all tearing our hair out trying to fix the problem but we can’t figure out why they are being so temperamental.
    Everyday its the same measurments, cooked at the same degrees in the oven and for the same amount of time. Its just a nightmare.

    If you could shed any wisdom it would be a big help

    1. Hello Em!

      Grey spots? I’ve never heard of oxidation doing that. My guess is it’s mold. I understand that your ingredients and baking times are the same. I would start by looking for excess moisture: in the environment, possibly even the flour (some batches have more moisture than others). The cheese is a also possibility. Has your purveyor changed recently?

      Usually when gougeres fall it’s due to a structure problem. And when I say structure I mean not enough flour in proportion to the fat and/or the moisture. Try a little more flour. If that doesn’t work try more flour plus more heat. If none of that works send me the recipe and I’ll help you troubleshoot it.

      Sorry for your frustration. I hope this helps.

      – Joe

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