Matt Brewing Co. Cuts Steam Consumption with Better Control
The Matt Brewing Company is a family-owned business founded in 1888. We make the Saranac brand of specialty products. Nick Matt and his nephew, Fred Matt, currently head the management team at the brewery. Under the leadership of these third and fourth generations of the Matt family, the brewery continues to craft beer to the exacting standards set forth more than a century ago. The brewery currently makes up to 30 varieties of Saranac beer during the course of the year, with distribution to about 20 states.
The heart of a brewing operation is boiling the wort. Brewing starts with the addition of malted barley grain and water to the mash cooker. Mashing allows the enzymes in the malt to break down the starch in the grain into sugars, typically maltose, to create a malty, sugary solution. After mashing, the resulting solution flows to a filter press that separates out the grain. Matt Brewing Company sells the filtered grain byproduct to local farmers as animal feed.
From the filter press, the solution, now called wort, goes into one of two steam-heated, 500-bbl (15,000 gallon) kettles for boiling (Figure 1). One of the kettles boils the wort while the other is cleaned and prepared for the next cycle. A manually operated coil for steam at the bottom of the kettle preheats the wort.
The boiling operation continues for 90 minutes, evaporating about 5% to 10% of the solution. This operation, which includes the addition of the hops, sterilizes the wort and affects flavor, stability and consistency. The hops provide bitterness and flavor. Following wort boiling, the solution goes through a period in fermentation tanks and finally packaging in bottles and kegs.
Steam pressure management is crucial. Depending on the atmospheric pressure, we need to control the steam pressure to get more or less BTUs of heat into the kettle. A pound of steam represents a certain value of BTUs. Steam cost is one of the most important energy variables Matt Brewing deals with. We were looking for a way to improve steam quality and reduce steam use. We consulted with R.L. Stone Co. (www.rl-stone.com), Syracuse, N.Y., on instrumentation to optimize the wort boiling operation.
The new instrument system measures and computes mass flow rates of steam to control heat for boiling the wort. As the wort temperature reaches the boiling point, the steam in the bottom preheat coil shuts off, and the recently installed automatic steam heating system takes over. From the steam header, the saturated steam flows through a control valve and an ABB Swirl flowmeter before reaching the kettle. (Figure 2)
The Swirl meter is a "vortex precessing" meter, somewhat akin to a vortex-shedding flowmeter, except that the Swirl meter has far better turndown at low flows and requires minimal upstream and downstream straight pipe, compared to other flowmeter types. We selected this type of meter because our piping geometry was tight, leaving very little space for straight pipe to condition the steam flow (Figure 3). The Swirl meter contains a built-in inlet flow conditioner and outlet straightening vanes, which saved the expense of re-piping the brewhouse.
From the flowmeter, the saturated steam flows to the top of an internal boiler in the kettle called a calandria (Figure 4). The calandria is a shell- and-tube heat exchanger. Wort rises through the tube bundle in the calandria while heated by the down-flowing steam, which begins to condense. A deflector at the top of the calandria distributes the wort and prevents foam formation. The internal caldaria efficiently provides both heating and mixing of the wort.
When starting a batch, the operator dials data representing the volume of wort in the kettle into an ABB ControlMaster CM10 flow computer. (Figure 5) This unit calculates the optimum mass flow rate of steam based on wort volume and feeds that rate to the ControlMaster CM30 single-loop controller as a setpoint. The CM30 provides indication, recording, math functions and proportional/integral control of the steam mass flow.