Introduction Of Dp In Lauter Tun And The Solutions To Control It

DP is the pressure difference between the dummy bottom and top measured with a pressure gauge, and what the pressure would be if the grain bed had no restriction on the flow of wort, and shown.

You can see that there are two pressure gauges connected to the fermenter: gauge #1 measures the pressure at the bottom of the screen, and gauge #2 measures the pressure above. Unlike my hypothetical example, neither gauge is connected to the bottom; however, this does not matter. Both gauges are calibrated in inches of water column. Therefore, pressure gauge #2 is higher than gauge #1, which must be corrected. Thus, with DP at zero, the reading of pressure gauge #1 is equal to the reading of pressure gauge #2, plus the difference in height between them. For example, we are running the first wort. gauge #2 reads 6 inches, gauge #1 reads 9 inches, and we know that gauge #2 is 4 inches higher on the fermenter wall. Therefore, with DP at zero, gauge #1 is reading 10 inches. If the reading is 9, the DP is 1 inch.

The negative pressure created in the lauter tank during the wort steeping process would have caused a catastrophic collapse.
In modern breweries, brewers have invented a number of special facilities to help check and control DP
Brewers have invented a number of special facilities to help check and control DP, including

1. Water level balancing tubes

A square inch column of water, 27.7 inches high, weighs 1 pound and has a pressure of 1 PSI. it is a mistake to express differential pressure in terms of PSI. This is not how it is usually done. DP is usually expressed in inches or millimeters of water column. Therefore, 0.64 PSI is equivalent to 17.7 inches, and we have a pressure differential of 10 inches. This is a crisis. The rule of thumb for commercial breweries is that 1 to 2 inches is optimal, 4 inches is good, and 6 inches is OK. When you hit 8 inches, it’s time to drop the rake and start lowering the flow rate. In fact, when the DP reaches 3 inches, I start lowering the rake. By 10 inches, we have to take remedial action – stop the runoff, make a deep cut with the rake, and maybe use a downspout to raise the bed.

2. SUS/clear glass vertical wort tank (buffer tank)

Usually used for 200L-2000L in microbreweries.
Its top should be positioned no higher than the bottom of the Lauer tunnel.
Automatic liquid level sensor can be placed inside SUS wort tank.
Whereas, there is no level sensor inside the clear glass tank.

3. Horizontal SUS wort grantor with inspection window

Usually used for 200L-2000L microbreweries.

4. Liquid level balancing column

Usually used in breweries of 2000L and larger.
Placement should be based on the height of the screen (false bottom).

5. Differential pressure transmitter

Installs pressure sensors and feeds data to the system’s PLC/control computer.
Typically used in large commercial and fully automated breweries.