Ultimate Guide to Proofing Croissants

Nervous about proofing croissants without a proofer? Here are all my tips, tricks, and troubleshooting tools so you can learn how to proof your croissants with confidence.

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What is proofing?

In the croissant making process, proofing is when you let the shaped croissants rest right before baking. During this rest, the yeast in the dough multiply and release carbon dioxide. This leads to 2 important effects:

• The gluten network in the dough traps this gas, creating air bubbles
• The fermentation process develops flavor

These effects are key to creating a light, fluffy, and flavorful croissant.

Improperly proofed croissants will turn out dense, flat, collapsed, dry, and/or oddly flavored.

Here is a simplified, conceptual overview of what happens during proofing:

1. Yeast consume sugar and generate gas
2. The gluten traps the gas. The croissant starts to expand and grow
3. If the gas bubbles expand too much or too much time has passed, the gluten will start to weaken. The croissant will start to collapse and flatten out rather than continuing to grow.

You want to find the sweet spot between 2 and 3 where the croissant has hit its maximum growth potential. That’s when it is “proofed” and it’s ready for the oven.

How to proof croissants at home

Temperature and humidity for proofing croissants

The goal of proofing is to promote yeast activity so that the gluten network inflates to its maximum potential, but not so much that it begins to collapse and lose structure.

There are 2 main factors to consider to create a good environment for proofing:

• Temperature – yeast need warm temperatures in order to multiply and produce gas. The ideal temperature is between 75F and 80F (24 – 27C), but even a difference of a few degrees can lead to significant changes in proofing time. Along with the needs of the yeast, you also need to consider the butter. Past 90F (32C), the laminated butter will start to melt and leak out of the croissants.
• Humidity – humidity prevents the dough from drying out. Dry dough is unable to stretch and create air bubbles, which restricts proofing, and the croissant will struggle to open up.

So your goal is to continuously maintain an ideal temperature and humidity until your croissants are fully proofed. I aim for ~80F (27C) and 70 – 80% humidity.

How to create a home proofer

If you are lucky enough to have a commercial proofer, it can generate the desired temperature and humidity on demand. As a home baker, there are 2 main ways I use to create the desired heat and humidity for my croissants.

1 – Proof croissants in a covered speed rack (preferred method)

You will need the following tools:

• Speed rack to hold the croissants
• Plastic cover for the speed rack to hold in the heat and humidity
• Large pot for holding water
• Portable hotplate for heating water
• Thermometer and humidity meter

How to set up the proofing system

1. Cover the speed rack with the plastic cover. It should have a zip open front for ease of loading and unloading trays.
2. Load the trays of croissants onto the rack. They do not need to be covered with plastic wrap
3. Boil a large pot of water
4. Place the hotplate on a tray at the very bottom of the rack, on a low temperature. I do around level 2, but the goal is to keep the water steaming but not simmering or boiling
5. Place the boiling water on the hotplate
6. Place an empty tray in between the steaming water and the trays of pastries, so they are not hit directly with heat. This keeps the croissants from overheating and leaking butter.
7. Zip up the plastic cover so that the steam and warmth is sealed in.
8. Monitor the temperature and humidity

Advantages of this system

• Can proof a large number of pastries at one time`
• Affordable
• Very effective at generating warmth and humidity

Disadvantages of this system

• Must monitor to make sure you don’t run out of water
• Must monitor to make sure it does not get too warm
• Trays can proof unevenly depending on the distance from the heat source

Note – you can do this system without the hot plate and steaming water. Instead, cover the croissants with plastic wrap and mist the inside of the rack with water. Be aware that it may take a very long time (8 – 12 hours) for the croissants to fully proof depending on the room temperature.

2- Proof croissants in the oven

You will need the following tools:

• An oven (hopefully you already have one, because you need to bake the croissants)
• Pot or tray for holding water
• Thermometer and humidity meter

How to set up the proofing system

1. Boil water and place it in a pot or tray at the bottom of the oven
2. Place a thermometer in the oven
3. Close the oven door and turn on the oven light. The oven light will help generate heat
4. Once the temperature reaches 80F (27C), place the trays of croissants inside the oven and turn off the oven light.
5. Periodically refresh the boiling water to continue generating steam and heat

Advantages of this system

• The most affordable and accessible solution

Disadvantages of this system

• Requires a lot of active monitoring
• Limited volume
• You need to remove the croissants out of the oven before you can preheat for baking. During the preheating period, the croissants will continue to proof so you will need to take this account

Proofing frozen croissants

Freezing croissants after shaping but before the final proof is a great way to manage prep and production. This way, you can prepare croissants on Monday but not need to bake until the weekend. Or you can prepare a large batch all at once, but only bake a few each day.

Proofing frozen croissants does lead to additional considerations to ensure an even proof:

• Frozen croissants need to be tempered before being placed directly in a warm proofer. If frozen croissants are not tempered, the temperature shock will make the outside of the croissant proof faster than the inside, leading to a dense core. Place the croissants in the fridge or room temperature before placing in a warm environment to more slowly raise the temperature.
• Freezing dough will reduce yeast activity. This can be combatted by adding some malt powder during the initial mix.

How to tell if croissants are proofed

Identifying when croissants are fully proofed is a tricky skill, and just takes practice.

Here are signs that your croissants are fully proofed, along with caveats from my personal experience:

• They jiggle when you shake the tray. It’s not just a little jiggle, it should be a full on wobble. And even if they jiggle, they might not be fully proofed, so check for other signs as well.
• They have grown significantly in size. They should look BIG, POOFY, and SWOLLEN. If you are questioning how poofy they are, they probably need more time.
• The layers have separated. Note that the degree of separation may vary depending on your formula and shaping. Also, if your croissants are dried out you, the layers will separate even if the croissants are not fully proofed
• The shoulders of the croissants should start melding into each other. If you see distinct “steps,” your croissants probably need more time. The lines between each of the shoulders should look slightly blurred.
• The tips of the croissants will start to droop. This is a sign that the gluten strength has reached its full potential, and is starting to weaken
• If you lightly poke the croissant, it should feel spongy and soft with a slight firmness, like a marshmallow or jello. You will feel small air bubbles pop beneath your finger.

These croissants are not fully proofed yet. While they have doubled in size and also jiggle when shaken, the layers have not separated and there is still a very clear delineation between the shoulders.

Here are signs that you may have overproofed and it’s time to hit the oven immediately. Some of these signs will vary depending on the gluten development and strength of the flour used:

• Rather than looking just poofy, it’s start to look and feel spongey
• If you lightly poke the croissant, it no longer feels slightly firm, just soft with no resistance
• The tips of the croissants are significantly drooping
• The croissant has begun to flatten out and lie completely flush against the baking tray, rather than having a slight curvature
• The croissant has started to deflate, and the surface looks wrinkly. This can especially happen if you shake or disturb the tray.

How long does it take to proof croissants?

In my experience, proofing croissants can take anywhere from 3 hours to 12 hours depending on the formula and proofing conditions.

Unless you are blessed with a commercial proofer, I strongly recommend going off of visual and tactile cues rather than purely the amount time. So many factors affect yeast activity that there is no singular universal proofing time, even if you are using the same recipe.

For example, here are just a few factors outside of temperature and humidity that affects final proofing time for croissants:

• The external weather and seasonality
• The dough temperature at the end of mixing
• Whether you activated the yeast before mixing it into the dough
• The type of yeast (e.g., fresh, dry, osmotolerant)
• Whether the dough was frozen
• The length and temperature of the bench rest

I use time more as a signal on when to check on my croissants rather than a rule to follow.

Troubleshooting proofing croissants

The vast majority of the time, your croissants will be underproofed. Really. When in doubt, keep proofing.

How to tell if your croissants are underproofed

Underproofing can range from super underproofed to just lightly underproofed. The first image shows a severely underproofed croissants. There is uneven collapsing, denseness, and tunneling. The second image shows a very slightly underproofed croissant. The middle is just a little denser and did not fully open up. Another ~15 minutes of proofing would have resolved this.

Here are signs of underproofing:

• The croissants leak butter in the oven. If your tray is covered in a pool of butter after baking, proof the next batch for longer.
• The layers look thick and dry rather than tender and flaky. This is because all the butter leaked out during baking.
• The exterior looks good, but the inside has collapsed in pockets (this is super underproofed)
• The croissant has a honeycomb, but the very center of the croissant is still tight and hasn’t fully expanded (this is slightly underproofed)
• The croissant is small for its weight. For example, when I was underproofing my croissants, a 100 – 120g croissant would come out the same volume as an 80 – 90g croissant from a bakery that was properly proofing its croissants

How to tell if your croissants are overproofed

For me, overproofing is fairly obvious post baking because the croissants will start to lose their strength and just go flat:

• The croissant has flattened out, and its noticeable from the exterior (extremely overproofed)
• The croissant is slightly flattened on the edges and “slumped” but still has a domed shape in the middle (slightly overproofed)
• Rather than a structured honeycomb, the interior crumb looks flat and spongey. Unlike underproofing, the collapsing will be uniform rather than in pockets

Tips to get better at proofing croissants

• Before worrying about proofing, make sure your dough development and lamination are spot on. If your gluten is under / over developed, or the butter is not sheeted in proper layers, the proofing is always going to feel off.
• Document extensively. Cut into the crumb of every single croissant you bake, and take a picture to track your progress. When you cut, use a serrated knife and make sure the croissant has fully cooled so you don’t squash the layers with a knife. For every batch, note the proofing temperature, humidity, and time.
• If you’re wondering about the tipping point between under and overproofed, put out multiple trays of croissants (e.g., 3 – 4) at the same time. Bake each tray 30 minutes apart. You will start seeing differences between the results, and it will help you understand where the inflection point is.
• If you’re constantly underproofing croissants, proof one batch for what feels like an egregiously long time (10 – 12 hours at 75F). Observe what happens at different points and what the final result looks like. If it’s still coming out properly proofed, you may have an issue with lamination or gluten development.