The following is not scientific fact, it is merely my findings from experience.
This bake was done to show what can happen with loaves that are proofed overnight in the fridge, and the effect of different types of slashes in the loaf.
Loaves kept overnight in the fridge have a tendency toward two things, a thick dryish skin (particularly if in a frost free fridge), and the core of the loaf is colder than the surrounding dough. These two factors can have a dramatic effect on your final loaf as you will see following.
It is my belief that :-
1. The colder core of the loaf will cause a tear in the loaf due to the outer section and the drier skin cooking before the core has had time to expand.
2. The type of slash is important in an overnight loaf to controll both the final shape of the loaf and its crumb structure.
The loaves were mixed as a single batch of dough starting at 3PM in the afternoon. They are all white bakers flour at 12.5% protein and the dough is at 64% hydration. At 7.15 PM they were shaped and put in cloth lined bannetons, and placed in the fridge.
At 6AM the following morning the first loaf was taken from the fridge, and the other loaves were taken out at 1 hour intervals (45 min baking time and 15 min oven re-heat time).
Each loaf was allowed to warm up for three hours, which is one hour longer than I usually allow as I wanted to maximise any initial slump but without overproofing.
The oven and baking stone were heated to 210C, and 15 minutes before putting each loaf in to bake the oven was turned up to 230C, and then turned down to 210C after the first 5 minutes of baking. On putting the loaf into the oven, 6 ice cubes were put into a tray in the bottom of the oven, and the top of the loaf was sprayed with water 3 times in the first 5 minutes. Total baking time was 45 minutes.
To show the flexibility of the skin of a one day loaf, which in theory is the same temperature right to the core, I post the following picture. This is made with the same recipe as the others.
As can be seen there is no tearing and a good shape.
The following pic shows the overnight loaf with the traditional “Vienna ” style of slash, you will note the tear and the rounded profile caused by the cooked bands of crust holding the loaf tightly. The loaf has not expanded to its full potential as you will see from the crumb pic shown later.
The following pic shows the effect of a slash down the centre line, it has allowed the loaf to spread (which is why I allowed the extra hour proof), but it has allowed the crumb structure to open up, pic shown later. There is still some tearing.
The next pic shows a slashing half way between the previous two, it has allowed some spread and opening up of the crumb, there is still a small tear but it has also held a better shape.
A good comparison of the three loaves can be seen following. The centreline slash has allowed a wide spread which actually shortened the loaf.
You can see the difference in the crumb structure in the following two pics. The first is the tightish crumb which has not been allowed to expand in the “Vienna” style slash and tight crust. The second is the more open crumb of the centreline type of slash.
As you can see, the type of slash you put in your overnight loaves can indeed affect the final result, both in shape and crumb structure.
(authored June 8th, 2006)