In last months’ Dough Doctor article we began discussing the causes for the development of the “dreaded” gum line. This month, we take a look further. Check out some common causes and how to remedy the problem:
Failure to cross stack the boxes of dough as they are placed into the cooler. Cross stacking the dough boxes in the cooler allow for more efficient cooling of the dough balls by allowing heat to escape from the boxes through the open ends. Failure to cross stack will trap heat in the box, allowing fermentation to continue for a longer time than desired. Additionally, condensation is also trapped in the box, resulting in dough balls that are over fermented (gassy) or blown and excessively sticky when trying to open the dough balls into pizza skins. In some cases, cross stacking cannot be done so we need to be a little creative in how we allow the heat and moisture to escape. For example, when using a reach-in cooler, there is seldom enough space to allow for cross stacking, but there is usually sufficient space front to back in the reach-in to allow for off-setting the dough boxes as we place them into the cooler, thus creating the desired ventilating effect.
Cannot be done so we need to be a little creative in how we allow the heat and moisture to escape. For example, when using a reach-in cooler, there is seldom enough space to allow for cross stacking, but there is usually sufficient space front to back in the reach-in to allow for off-setting the dough boxes as we place them into the cooler, thus creating the desired ventilating effect.
Another option to consider when cross stacking isn’t an option is to oil the dough balls and place them into plastic bread bags, closing the open end by twisting it into a pony tail and tucking it under the dough ball as it is placed onto a sheet pan or shelf in the cooler. The thin plastic bag allows the dough to cool quite well and the snugness does not allow for the development of condensation within the bag or around the dough ball. If individual plastic bags are not used, the dough balls can effectively be placed onto aluminum sheet pans, lightly oiled and placed into the cooler for a couple of hours. A food contact-approved plastic bag can be slipped over the tray, allowing the dough balls to effectively be stored for as long as three days without and problems.
Allowing the dough to bulk ferment prior to scaling and balling of the dough. By allowing the dough to bulk ferment prior to scaling and balling the dough what we end up with is a less dense, more gassy dough being formed into balls. In this condition, the dough balls are more difficult to cool as the gassy nature of the dough creates an excellent insulation, thus impeding rapid and thorough cooling of the dough balls. It also increases the possibility gassy or blown dough, which is typically addressed by reducing the yeast level, with the dough suffering the afore mentioned failure to rise in the center section leading to the potential development of a gum line. It is better to take the dough directly to the bench for scaling and rounding soon after mixing, as the more dense dough will be more conducive to rapid and uniform cooling without problems related to gassiness.
Failure to take the balled and boxed dough directly to the cooler.
In some cases we see the dough balls handled and managed correctly right up to the point where they are ready to take to the cooler; however, they are then set aside and allowed to proof, in the ball form, for a specific period of time. Again, this practice results in the dough becoming less dense, more gassy, and more difficult to cool, or at least cool uniformly. In severe cases, this can lead to the dough blowing, or at least over fermenting in the dough boxes to the point where they are difficult to individually remove from the dough boxes due to the dough balls growing together. Or, in really severe cases, the dough balls can grow together to create a solid mass of dough in the box, ultimately resulting in loss of the dough, or at least the need to re-scale and re-ball the dough and then wait for it to loosen up enough to form it into pizza skins. Again, the incorrect action is to simply reduce the yeast level to a point where this is no longer a problem as you are setting the stage for a gum line.
Failure to allow the dough to adequately temper at room temperature before opening the dough ball into a pizza skin, dressing it and taking it to the oven. (This can be especially problematic when working with a conveyor oven)
In this case you must remember that any conveyor, air impingement or otherwise, will only put a specific amount of heat into the dough. This is controlled mostly through baking time and temperature, but air impingement baking also allows for the adjustment of airflow over the pizza while it’s being baked. In every case though, these baking parameters are fixed and locked into place when the pizzas go into the oven, so if we do not allow the dough sufficient time to warm up slightly after removing it from the cooler, we can be faced with trying to bake pizzas on dough that varies in temperature. With those fixed baking parameters, this means that the pizzas made using the colder dough may not be baked as thoroughly as those baked using a warmer dough. The result is that if the oven is set up to provide the minimum bake time needed for the pizza (with normal temperature dough), those baked with a lower temperature (cooler) dough may be insufficiently baked to the point where it will exhibit some collapse after baking to create a gum line. In cases like this, it is better to set the oven up to provide a slightly longer baking time than the absolute minimum as this will allow for enough latitude in baking to ensure thorough baking of any pizza made using a dough ball at any reasonable temperature.
Sheeting or stretching the dough too thin when opening the dough ball into a pizza skin. Forming the pizza skin too thin, especially across the center section, on thin crust pizzas can result in a condition where the heat to the bottom of the pizza conducts right on through the crust and is absorbed by the sauce only to be dissipated as steam. When this happens, the bottom crust may not get sufficiently hot to fully bake and results in an instant gum line. Even if it does bake, the amount of crust actually developed is so thin that only the very surface has any crisp to it, leaving the rest of the bottom limp and soggy. The use of a sheeter/dough roller seems to exasperate this condition due to the fact that the sheeted dough has had most of the entrapped air and fermentation gas forced out of it, making it very dense and prone to this problem even at dough thicknesses approaching 3/16 inch. If a sheeter is used to open the dough balls for thin crusts, it is recommended that the sheeting rolls be set so as to give a sheeted dough piece that is about 75 percent of the desired diameter. The dough should then be opened the rest of the way by hand.
Following this method, we have had excellent results getting thin crust pizza skins with an even thickness, that still retains sufficient gas to spring in the oven, thus preventing the heat from passing all the way through the dough, and resulting in a finished crust that has a uniformly crispy texture to it with no signs of a gum line.
Tom Lehmann is a director at the American Institute of Baking in Manhattan, Kansas.