Fermented, laminated pastry is made by encapsulating a lamination butter component with a fermented dough component in a process called the “Lock-in.” Then, through a sequence of reduction sheeting and folding, you create layers of dough and butter to produce a light and flaky pastry from which you can make croissants and other popular pastries. A crucial part of good pastry making is controlling both the dough’s temperature/fermentation and the butter’s temperature throughout the makeup process until the pastry is proofing.
It is essential to prevent the pastry from skinning and proofing throughout the lamination stages, as uneven layers will form in the pastry because of expansion, and flakes of hard dough caused by skinning will ruin the pastry. Once you begin the process of laminating the pastry, you should delay or stop all fermentation by using various means of chilling, in which both the dough and the butter components should remain cool throughout the entire pastry- making process. This should include all rest periods. In cool conditions, you can make the pastry entirely at once by giving the pastry all its folds, one after another, and then chilling the pastry for an hour before final sheeting. In warmer conditions, it may be necessary to chill the pastry well in between folds, or the butter may melt. Whether operating in warm or cool climates, you should chill, rather than freeze, the pastry at this stage of the process.
When you’re in the “Lock-in” stage, I recommend a dough temperature of between 2 – 3°C and a butter temperature of between 9 – 13°C. Butter performance varies from one brand to another. Still, it needs to be plasticized and flexible before use, so it will flow within the dough component and create a perfect butter ribbon inside the dough when reduction rolled. Industrial refrigerators, freezers, blast chillers and Cryopack® ice blankets are essential tools for good pastry production. Ice blankets contain pockets of distilled water, are food-safe and freeze at or slightly below 0°C. Many professional kitchens and bakeries also have air-conditioned rooms to control the environmental temperature (16°C) for pastry consistency. Most home bakers do not have the luxury of such space or equipment. Even though many culinary schools lack equipment such as blast chillers, it is a widespread practice to wrap the pastry in a plastic sheet and chill it on a metal tray in the freezer at -18°C. Covering the pastry in a thick plastic sheet is essential to prevent frostbite on the surface. Additionally, the plastic keeps the pastry from becoming wet and sticky when using the ice blankets or blast chillers. When you chill the pastry this way, the bottom part in contact with the frozen tray will cool rapidly through touching or conduction.
In blast chillers and freezers, the sides and top of the pastry take longer to chill, as they rely on the circulation of chilled air or convection to cool them, which creates an imbalance in the chilling process. Often, the pastry’s bottom, corners and edges begin to freeze quicker than the rest and cause problems when processing.
The freezing is not even throughout the pastry block, and the pastry has different temperatures in different areas, such as the top, sides and, more important, in the core of the pastry. The pastry must be chilled quickly and not frozen during the makeup process, as freezing damages water crystals in the dough and both the water and fat crystals in the butter. If frozen, the dough portion of the pastry will split and crack. The butter element will become hard and brittle and shatter into pieces, giving a marbled aspect to the pastry and destroying the layers created in the makeup process. Pastry makers have often used two frozen metal trays to chill pastry quickly. The trays, placed like a sandwich on the sheeted pastry top and bottom, quickly cool the pastry’s outside layers. However, the pastry rapidly takes all the coldness out of the trays, and they need to be chilled several times again to be effective at maintaining a low temperature.
A modern approach in the absence of blast chillers is to use “Cryopack® Ice Blankets.” These are available from the manufacturer and also on Amazon and they are worth the investment to serious pastry makers. For home bakers or hobbyists, two packs of frozen corn or peas work equally well as ice blankets for small quantities of pastry, which is an inexpensive option and yields excellent results; https://youtu.be/-WZ9w0gPjyg. I first saw the use of ice blankets in competitive pastry processing in the mid-2000s during the Coupe du Monde de la Boulangerie competitions in Paris. Team USA’s viennoiserie candidate, Peter Yuen, and the Asian viennoiserie candidates made use of ice blankets. They are excellent for rapidly chilling laminated pastry as the pastry block is encapsulated top and bottom, physically touching the ice blanket. As a result of this direct contact between the pastry and the ice blanket, a very efficient, uniform and rapid chilling of the pastry block is possible.
In the “Core line” illustration at the end of the page, we illustrate a folded block of pastry (gold) with a book fold or a 4 fold wrapped in an ice blanket (blue). The pastry touches the ice blanket surfaces top and bottom, and this direct contact chills the pastry down quickly.
The thicker the pastry, the longer it takes to cool to the core. On the left side of the diagram, the pastry block is much thicker (30 mm) than the one on the right (15 mm). The black line illustrates the core or center of the pastry block. The pastry chills from the outside into the core; when wrapped in ice blankets, the pastry has the dual effect of cooling by the ice blanket’s top and bottom. Blast chillers achieve the same effect, but you have to take care not to freeze the pastry.
The pastry’s thickness is important when chilling; the thinner it is, the more rapidly it will chill. In the Core Line diagram on the left, the ice blanket/blast chiller needs to chill through 15 mm of pastry, top and bottom. There is a danger that the pastry will begin to proof in the core before the chilling of the ice blanket can influence it. The same pastry block is sheeted down to 15 mm on the right side of the illustration. The ice blanket/blast chiller must only chill through 7.5 mm of pastry thickness to reach the core, so it cools twice as quickly. Therefore, I always recommend sheeting folded pastry after creating the final folds to between 12 mm and 15 mm before chilling it in the blast chiller or the ice blankets.
Understanding Core Temperature in Proofing Pastry
As discussed in understanding the core temperature in chilling pastry earlier, we refer to the center of something as the core or the middle. Any pastry that is coiled when shaping, such as croissant, pain chocolate and pain aux raisin, will have a spiral profile with layers coiled on top of one another, a core and an outside. The pastry is a poor conductor of heat, so its exterior will rise to the temperature of the proofer faster than its core. When pastries, such as croissant and pain au chocolat, have cores that are far from their outsides, it exacerbates this problem. The outside of the pastry in a proofer will slowly begin to heat up. The heat will take some time to permeate the pastry to its core. Croissant pastry is generally proofed at approximately 26°C to 28°C for 2 to 3 hours and 75 – 80% humidity. It is inadvisable to proof croissant pastry at a higher temperature unless you have special types of butter with higher melting points. The dough will ferment quicker, giving a more bitter taste, and the butter may melt inside the dough layers and turn to oil, destroying the butter layers created during lamination. One brand of butter sheets I have used in hot equatorial countries is Anchor Butter. Anchor produces a choice of two butter sheets withdifferent melting points of 34°C and 37°C, respectively.
As illustrated in the Core Pastry Diagram of a proofing croissant, the outside surface begins to heat up and proof first. It takes some time for the proofer’s heat to get to the pastry’s core and heat it. A honeycomb crumb structure is a good indicator of a successfully proofed pastry. A thick, gummy, non-aerated core indicates insufficient proof time and baking the pastry before the pastry core has opened and is fully proofed. It is the most common fault in baking laminated yeasted pastry.
Jimmy Griffin is a sixth-generation baker and lecturer at TU Dublin, Ireland, with a Master’s in Food Product Development and Culinary Innovation. He teaches globally, including in Germany, the UK and Japan, and is a renowned international bakery judge. A competitive baker, Griffin won bronze at the 1997 Coupe D’ Europe de la Boulangerie and coached the Irish bakery team. He is also a licensed pilot, judo blackbelt instructor and author of six acclaimed books, including “The Art of Lamination” and “Panettone – The King of Bread.” He was recently named a global ambassador for Anchor Butter and taught in Japan to more than 4400 students.
(This article appeared in the Winter 2025 issue of Pastry Arts Magazine)
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