Baker’s Topic – Slashing the Loaves
Slashing the loaves with a sharp blade just prior to loading them in the oven is one of the most craftsmanlike pursuits in baking.
While it can often be referred to as “decorating” within the bakery, it is actually much more than decoration. Its main purpose is to allow the loaf to expand evenly and handsomely when the loaf is subject to the rapid expansion that occurs when it is placed in the oven.
Subjected to such massive heat all around it and particularly driving from the oven floor into the base of the loaf, the existing gases within the loaf start to expand. Further, the yeast reacts to this new burst of warmth and has a final flurry of excitement, creating more gas before expiring at around 60 degrees C. Hence, the loaf swells surprisingly quickly. The name for this expansion is “oven spring”. When it is a neat line running along the top of a tinned loaf it can be referred to as “oven break”. Unless the skilled baker intervenes the rapid expansion can cause the loaf to distort, perhaps leaning over, or changing shape from straight to curved, perhaps even blowing a hernia out one side.
The cutting or slashing of the loaf’s surface is done to control the oven spring. The blossoming of such energy will be released through the slashes, opening them out neatly and making the bread look so beautiful in its final form. Indeed the decoration itself can be pretty, but great beauty occurs where the slashes provide that lively contrast between the original crust, the ridge of the cut, and the different texture of the inner portion of dough erupting out through the opening made by the cut. The handsome loaf is a contrast of colour and texture.
A few tips
The blade must be extremely sharp, and that is why old-fashioned razor blades for shaving are so popular. I attach the razor blade to those slender sticks made as coffee stirrers, (like an ice-cream stick), They are vulnerable to pitting and rust, losing their edge after just a day or two, thus need to be constantly changed.
Razor blades, while preferred by many craft bakers, are not the only tool. Any type of knife does the job, provided it is extremely sharp, and has a blade length suited to what loaf you are slashing. My French pen knives are made of carbon steel which sharpens easily and, like a butcher, they are sharpened repeatedly in the bakery.
You have to learn through trial and error how deep to cut. A general rule is a deeper cut is required when the loaves are going into the oven a bit early, which means oven spring will be more pronounced. When the loaves are over-proved (you are having a bad day) there are types where it is best not to cut at all since the impact of knife or razor might deflate the loaf. Wholemeal would be such a type.
Cutting sticks is a joy since their slashes can open out so generously. Don’t apply the knife transverse to the slender shape; instead make the cuts run almost straight down the stick’s back, with the next cut starting right beside the end of the previous one. Experience baguette cutters will urge you to hold the blade leaning to one side as you cut, avoiding the vertical.
Enjoy your cutting, enjoy being the craftsman baker who controls the activity in the oven.