What causes a gum line just below the sauce?
A: They don’t call it the “dreaded gum line” for nothing. A gum line can be caused by a number of different things, and some of them are inter-related, but the “kicker” is that it won’t go away until you address the causative factor. This is where things can get interesting. The main factors that we have found to contribute to the development of a gum line are as follows, presented in no particular order:
- Excessive thinning of the sauce. A thin watery sauce that exhibits a tendency to separate upon standing will develop a wet soggy area just below the sauce, leading to the development of a gum line. The reason for over thinning of the sauce may be a sense of false economics resulting from adding additional water when the cost of the sauce increases. It also might be in response to adding onion and/or garlic to the sauce without sufficient heating to neutralize the enzymes responsible for catalyzing the pectin in the tomato –– resulting in their gelling, and/or an excessively thick sauce. This is then addressed by adding more water to the sauce, further diluting it, resulting in water separation. From all indications, it appears that a sauce solids content of about 11 or 12 percent seems to work the best in terms of both sauce performance and economics.
- Pre-saucing of the pizza skins ahead of time for in-store use or in making take and bake pizzas. Pre-saucing of the skins should be avoided whenever possible, but when it must be done, either to help keep up with orders during busy periods, or when making take and bake pizzas, the pizza skins should be given a very light application of oil prior to saucing. This will help to prevent moisture migration into the dough by creating a barrier on the surface of the dough. Pre-saucing of pizza skins with an overly thinned sauce can be especially problematic due to the extreme tendency of the sauce to exhibit syneresis (water out) between the time of sauce application and actual time of baking.
- Too much sauce used on the pizza. When too much sauce is used on the pizza, it becomes more difficult to bake out thoroughly. Due to the sheltering effect of the sauce on the underlying dough/crust, the water separation from the sauce through syneresis is magnified due to the greater amount of sauce present. In addition to a potential gum line, this problem is normally accompanied by a decided tendency of the pizza toppings to slide off of the pizza slice with the first bite.
- Insufficient yeast level. This can result from a number of things. Incorrect dough formulation (not enough yeast), but more commonly it is the result of action taken to address blowing of the dough. When the dough blows, the first thing that is usually done to correct it is to reduce the yeast level. This does work, but in more cases than not, it results in a yeast level so low so as to inhibit proper rising of the dough with a full load of toppings as it should during the early stages of baking in the oven. We typically see this happening in the center section of the pizza. The thinner, more dense dough is now a better heat conductor. And, as such, it allows the bottom heat of baking to more readily pass through the dough/crust only to be absorbed and dissipated by the moisture in the sauce. This results in a bottom crust that is not thoroughly baked, which then collapses upon removal from the oven, to create a gum line.
So, why did we reduce the yeast level in the first place? The most common reason is due to some form of temperature abuse or incorrect management of the dough. Temperature abuse can include having the dough at too high of a temperature after mixing, while incorrect dough management can be the result of allowing the dough to bulk ferment prior to scaling and balling of the dough, making for a more gassy dough which is more difficult to cool when it is taken to the cooler for storage.
Many times we find failure to cross stack the dough boxes in the cooler to be the culprit. In this case the boxes are nested or covered as soon as they are placed into the cooler resulting in heat being trapped in the dough box, thus allowing the dough to continue to ferment rather than being cooled down as desired. Along similar lines, the dough balls can also be allowed to ferment outside of the cooler for a period of time prior to going into the cooler. This results in the dough balls proofing/fermenting, and developing more and larger gas cells which work to insulate the dough, reducing the rate at which they are cooled, causing them to blow or sporadically blow. Again, reducing the yeast level might seem like the thing to do, but it will also impact the way the dough rises in the oven to potentially create, or add to the creation of a gum line.
The time of the day when the dough balls are made and taken to the cooler can also lead to a reduction in yeast level. In this scenario, the dough might be made in the morning hours before the store opens, and after all of the dough balls are in the cooler, we begin our regular traffic pattern in and out of the cooler for the remainder of the day. The constant opening of the cooler door leads to a higher operating temperature during business hours than during the night time hours leading to excessive dough fermentation and excessive dough ball growth or full scale blowing of the dough. The solution here is to prepare and process the new dough in the later evening hours so the dough will be placed in the cooler during a time when there is reduced traffic into the cooler, and the dough will be exposed to the lower night time operating temperature of the cooler to achieve more effective and consistent cooling of the dough balls.
Tom Lehmann is a director at the American Institute of Baking in Manhattan, Kansas.