Dear Mr. Walker,
Reducing the heat transfer (so temperature and/ or airflow in your case) in the first zone will to some extend increase spread. The reverse is also true of course.
If you are able to play around with your formulation and/ or materials that you could consider:
- sugar crystal size and type of sugars
- total sugar
- Total fat and type of fats
- Flour type
- type of leavening
The spread of a cookie is very dependent on the recipe (water, leavening agents, fat and sugar as well as the characteristics of the flour) and how you add the ingredients, especially sugar, in the kneading phases. The higher the fat/sugar content, the higher the spread. Even the granulometry of the sugar has a great influence. The finer the sugar, the higher the spread.
In relation to the oven, it is always advisable to start with a smooth profile, peaking in the 3rd zone of the oven. With the extractions closed in the first zones and then with a higher percentage of opening as you advance in the oven. In this way you will achieve a better distribution of moisture inside the cookie, reducing the possibility of checking.
On the other hand, if you want to obtain a more cracked surface, it is advisable to open more the extractions in the 2nd and 3rd zone of the oven, to favor the escape of vapors that escape through the biscuit, forming a superficial crack and also a greater spread.
Dear Mr Walker
Could you please tell me what kind of oven at present you are having in your factory. Also what type steam (humidity) control in the oven. Because oven to oven this setting changed to get the spread
Dear Mr. Richard
Sorry for the delay in replying though you replied on 26th june itself. I could get time now only to see this.
In forced convection oven normally spread is more due to oven type and the circulation it has to have maximum utility of the heat. To control the spread on plain steel band you need to reduce ammonia and water--( pl check too much reduction of water will have problem in your depositor). Also initial zone top and bottom temperature difference should be minimum only. Humidity control in initial zone keep only 50%.
To get the cracks on the top of the cookie, keep maximum humidity in the initial zone and keep the top temperature more than bottom and keep the forced convection heat on the top more in the initial zones. Colour of the cookie can be adjusted at the last zone if it becomes too dark due to initial heat set up. Please try and let me know.