A batter holding tank 1.5 – 2.0 times the size of the mixer should be used with some slight agitation to avoid sedimentation/separation. A low rpm paddle to maintain the suspension of flour in water provides the slight agitation.
Ideally the holding tank should be water jacketed to maintain batter temperature. A relatively fine mesh sieve (2-3 mm) is located on the upper rim of the vessel and the batter from the mixer should pass through this into the tank. Any sediment found on the sieve will be indicative of how well or poorly the batter has been mixed as well as giving information with regards to the suitability of the flour to water ratio (solids) for that particular recipe.
If using enzymes to modify the characteristics of high solid batters or flours, which may be causing problems in a given recipe, the resting period in the holding tank may need to be adjusted. A no-time batter is considered as the normal or standard retention time in the holding tank. Depending on the throughput of the ovens being supplied this may be 20-30 minutes, which should be enough for the enzyme to modify the gluten.
Experience however will dictate if this should be longer and can be checked by taking further viscosity samples at intervals from the batter in the holding tank.
Specifications for a typical wafer oven requirement, from the product point of view, could be suggested as follows: guaranteed capability to bake to even moisture, thickness, texture and color over a baking range of 1.5 – 2.5 minutes.
a) would always be established based on recipe used but would expect to be within the range of 1–2%
b) not to vary from sheet to sheet by more than +/- 0.25 %
c) not to vary within each individual sheet from centre to diagonal corners by more than +/- 0.25 %
Thickness: to give a regular deposit of batter, to produce sheets of regular even thickness throughout with variation no greater than +/ -3.5 % (e.g. +/- 0.1 mm on 2.7 mm sheet).
Texture: to produce sheets of open and even texture throughout.
Color: to produce sheets of even color throughout with no obvious high or low spots.