What is the windowpane test for bread dough?

How do you know when your yeast dough has been kneaded long enough? 

The terminology used in recipes is both subjective and potentially confusing. “Knead the dough until it’s smooth and supple” or it feels “bouncy and elastic under your hands.” Or it feels like your earlobe — or a baby’s bottom.  

Photography by John Sherman; food styling by Liz Neily

How smooth is smooth enough? What if you don’t have a baby around for comparison?  

Don’t despair. There’s a quick test to find out if your dough is sufficiently kneaded. It’s called the windowpane test, and it lets you actually see with your eyes how strong the dough is. 

How does the windowpane test work?  

When you think your dough is sufficiently kneaded, grab a hunk about the size of a ping pong ball. Flatten it between your fingers, as though you were making a tiny pizza. Let it rest for a couple of minutes, then flatten some more. Very gently pull on opposite ends to stretch out the middle.  

As you pull, the dough in the center will become thinner and thinner until at some point it tears. This may happen almost immediately, or the dough may stretch so far you can see light through it; this is called “achieving the windowpane.” The point where the break occurs tells you just how developed your dough is, and whether or not you should continue to knead it. 

What’s happening here? 

In order to rise and hold its shape, yeast dough depends on gluten, a series of joined proteins that form a stretchable web that traps and holds carbon dioxide emitted from the yeast as it feeds. As you knead dough you “exercise” the gluten, both strengthening it and aligning it into its desired web. The stronger and more elastic that web is, the more thinly it can stretch itself without breaking — and the better your bread will rise.  

PJ Hamel

The windowpane test lets you see just how strong and elastic your dough is at any point. Try it when you’ve first started kneading, and the dough will break almost as soon as you start stretching it. But after sufficient kneading, you’ll be able to stretch it much more thinly.  

So, is the goal to be able to stretch the dough as thinly as possible?  

Sometimes yes, sometimes no. The windowpane test isn’t “pass or fail;” it simply tells you what stage the dough’s at in its development, with your goal being dough that’s perfectly developed — its gluten at full strength — just before it’s shaped. 

General rules of thumb: If you’re baking bread that’s going to rise in the bowl (bulk ferment) for only a short time before being shaped (say, an hour or so), then you want the gluten almost fully developed. When it’s sufficiently kneaded you should be able to stretch the dough until you can start to see light through it in spots. 

But if you’re baking bread that’s going to rise in the bowl (and/or in the fridge) for hours before being shaped, then you want the gluten much less developed. When you stretch this dough, it may only stretch half an inch or so before tearing — and that's OK, because the dough’s gluten will continue to gain strength during those hours it’s resting.  

Barb Alpern

When should you use the windowpane test? 

Perform the windowpane test anytime you’re uncertain about where your dough is in the development process — the journey from “This dough is just a sticky blob” to “OK, it’s ready to shape.” This uncertainty can spring from a number of sources: 

• You’re a new bread baker and aren’t yet able to judge how well dough is kneaded simply by looking at it and feeling it. You’ll learn these skills over time and through practice, but in the meantime, do the windowpane test.  
• You’re using a new recipe and aren’t familiar with what the dough should look and feel like during its various stages of development. 
• You’re using a familiar recipe but substituting a different flour — which can be higher, lower, or different protein than what you’re used to. Protein becomes gluten when combined with water and kneaded, so dough made with flour with a lower (or higher) protein level may look and feel quite different than your norm. 
• The dough needs an “intensive mix” (long kneading time), which is a hallmark of many enriched doughs full of butter, sugar, and eggs, such as brioche. Arturo Enciso of Gusto Bread says, “[The windowpane test] is especially important for us in our enriched doughs. Adding butter, sugar, egg, etc. will weaken the dough, so a longer mixing time is typical … Not [using] a windowpane test for dough like this could result in leaking butter, dense bread, and lacking flavor.” 

Photography and food styling by Liz Neily

• Dough that gets almost all its development from kneading (especially kneading using a stand mixer) rather than the passage of time. “I use the windowpane test most often when I’m mixing yeasted doughs that I’m going to bake within a few hours of mixing,” says Jennifer Latham, author of the forthcoming book Baking Bread with Kids. “These doughs need to get more development in the mixing phase than sourdough [or other doughs relying on extended fermentation for their development]. In the case of sourdough, time and turns (gently stretching and folding the dough while it ferments) will do some of the work of developing the gluten, so the windowpane test isn't as relevant.” 
• Sourdough undergoing an extra-long bulk ferment. Sourdough can be tricky, as its acidity can gradually break down its gluten and weaken the dough’s structure over time. If you’re worried that you’ve left it to ferment too long — say, your sourdough has been in the fridge for three days — do the windowpane test just before shaping. If it doesn’t pass, your best bet is to make flatbread!    

Does the windowpane test work with whole grain dough?

Because the bran in whole grain dough can damage the developing strands of gluten, the windowpane test won't work the same as it does with white-flour doughs. You may eventually develop a windowpane, but it’s more likely to happen if the dough has rested overnight, giving the bran a chance to soften its sharp edges.  

Ready to take a deeper dive into developing yeast dough? See our two-part series: Why kneading isn't always the best way to develop bread dough, followed by Why this pro baker doesn't knead. 

Cover photo by Rick Holbrook, food styling by Kaitlyn Wayne.