Improving Output of Your Current Brewhouse (Part I: Mashing & Lautering)

Part 1:  Mashing & Lautering

Efficient utilization of equipment is a concern in any brewery. Whether large or small: saving time means saving money. The heart of the brewery, the Brewhouse, holds the most opportunity for time savings. Not all suggested solutions require major equipment overhauls or purchases with the right equipment.

Whether a brewery has two or five vessels in their Brewhouse, there are  five key process steps that cannot be skipped, truncated, avoided, or bypassed:  Milling and weighing up, Mashing, Wort extraction(including spent grains removal), Wort boiling, Wort cooling (including trub separation).

Generally speaking, these steps create one linear brew cycle and looking at the mash and lauter activities is the first in our series of articles about ways to get more production out of your Brewhouse!

Step 1: Mash In (combo Mash/Lauter vessel)
Hydrated milled grains should fill the vessel. This process involves strike water which must be consistent in flow and especially temperature. Balancing that strike water with a consistent flow of milled grains is also important. The end result should be well distributed, hydrated grains at the target temperature. To speed this process up, considering reviewing the following:

• Capacity of existing grist conveying equipment. This may be as simple as a speed increase, or worst case a larger conveyor.
• Capacities of existing hot and cold liquor pumps. This too may be as simple as an impellor change or a larger pump. In both cases it’s very important to ensure the grain transfer completes ahead of the mash in water, so as to effectively purge the hydrator.
• Drop pipe.  For systems using a gravity drop from the grist case to mash mixer or mash lauter tun, then this may involve a larger drop pipe, to work in tandem with item 2 above.
• Hydrator design.  In most cases this would need reviewing to ensure it has the capability of presenting a fully homogenous mash to the respective vessel at the increased “mashing in” rates

This relationship between hot and cold liquor is very important to strike water temperatures and flows and can be fine- tuned when using two pumps much easier than when relying on fluctuating city water pressure. The temperature of cold liquor is also very consistent compared to city water, which will change with season and usage.

Step 1a: Mash In (dedicated Mash Mixer)
In the case of a dedicated mash mixer, small deficiencies in the hydrator, or unexpected lower strike temps can be compensated for during the residence time in the mash mixer. This is due to its steam jackets which should be sized for 1o C temp rise per minute. Mash mixers, hydrators and agitators should have the ability to easily create a homogenous mix and temperature without imparting shear to the mash.  Items to review here include:

• Agitator design and speed .This is crucial to avoiding shear, providing adequate mixing and uniform temperature. Speed is a function of the agitator diameter.  The use of variable speed control drive is highly recommended.

Step 1b: Mash Transfer (dedicated Mash Mixer)
Opportunities for time savings can be gained by looking at the mash transfer system.  Those to review include:

• A Larger pump and transfer piping.  The design needs a maximum pump speed and line velocities that will ensure mash is presented to the lauter tun in optimal condition for wort extraction. We consider 10 – 15 minutes as the ideal transfer time.

Step 2: Lauter Tun.
Of all the Brewhouse vessels the Lauter tun is generally the longest residence time, and presents greater challenges for time savings.  We are looking to provide exceptional wort quality, efficient extraction of the sugars all within a reasonable time frame.  Bed loading, grist spectrum (grind), uniform distribution of the mash, design of the raking machine, wort collection system and false bottom all play their part in achieving the goals and while not easy can be handled when starting with a clean sheet of paper. There are however certain things that can be considered with an existing installation:

• Check condition of the false bottom. Excessive radial and circumferential gaps between the plates will allow solids migration into the wort stream which is detrimental to quality, time and efficiency.
• A large under-plate void.  If one exists, it could impact extraction efficiency.
• Rake design and density.  This affects wort collection time and extraction efficiency.
• Number of wort run-off points and the collection header.  If not balanced or sized correctly affect time and efficiency.
• Variable speed rakes.  With the ability to be raised and lowered will only serve to enhance, quality, time and efficiency.

Step 3:  Vorlauf

With a dedicated mash mixer and lauter tun, the Vorlauf step can be started around the mid-point of mash transfer.  However, there is one improvement to consider:

• Add turbidity meters.  These provide an analytical method to determine when acceptable clarity has been achieved and initiate forward flow to the kettle.  They also provide an actual quantitative value that notifies the brewer that it’s time to start runoff, or automatically take the brewhouse to the next process.

Step 4:  Runoff/wort collection (combo Mash/Lauter vessel)

To ensure the sparge system has the ability to match the wort collection flow rate(s) and that the sparge distribution is even on the grain bed, review the following:

• Run high gravity first.  Consider running the higher gravity and viscous first worts off at a slower rate to reduce the rise of differential pressure across the grain bed. As the gravity and viscosity decline it should be possible to increase wort flow rate resulting in a net time saving.
• Run-off ports.  Below the screen enough run-off ports should be present so the wort has a direct path to the collection ring(s).
• False Bottom. The screens design is very important.  Subject to bed loading within an existing lauter tun, upgrading to a milled screen could provide quality, efficiency and cycle time benefits.
• Differential pressure.  This should be controlled via pressure transmitters above and below the screen. This gives the brewer and automation good reference as to the runoff capabilities of the entire setup for a given recipe.

If you would like to discuss brewhouse equipment with one of our Sales Managers, please email us at sales@sprinkman.com .  Look for our second installment, “Improving Output of Your Current Brewhouse Series:  Kettle & Whirlpool”, in our August newsletter.