Cold brew coffee takes time, patience, and most importantly, the perfect grind. MPE designed the industrial-grade GPX and GPC-140 coffee grinders to meet the demands of small batch cold brew makers looking to brew the best quality product.
The precision disc-style GPX and GPC-140 grinders are designed for capacities of 200 – 1,000lbs/hr and run continuously without diminished grind accuracy. The GPX uses 5.5 inch diameter “diamond hard” grinding discs that are precision-cut to optimize cutting action with infinite adjustment control, resulting in a cool, uniform coffee grind for optimal brew performance. The GPC uses larger 7.1 inch diameter discs for greater volume.
Consistent grind is critical when steeping for long periods of time, and can influence the quality of the coffee you serve. Ensuring grind uniformity, in combination with cold brew steeping methods will ultimately deliver the smooth, round taste identified in a truly well-made cold brew beverage.
Good coffee capsule and pod production requires more than just roasting, grinding, and packing coffee into pods and capsules. It also requires an extra step to make sure the density of the ground coffee is optimal for capsule and pod brewing. To understand how density works and its role, we must look at the following:
The coffee particles’ shapes when they exit the grinder and how to optimize their shapes for greater density
The use of water pressure in capsule and pod coffee makers and how density is a factor to increase extraction
Coffee’s shape when it leaves the grinder
Coffee particles are not smooth and spherical when they exit the grinder. They are jagged and non-spherical, which means they tend to fill the capsule inefficiently. With less coffee in each capsule, the results are a weak and under-extracted cup of coffee.
Using a process called densification, the coffee particles are literally rounded out, sometimes even having many smaller fines clustering together into larger sized particles. On a microscopic scale this means considerably more total dissolvable solids can fit into the same amount of space.
The role of water pressure, and density as a factor
Densification is not a new concept. Tamping an espresso is basically a form of densification. It not only serves to fit more coffee (and dissolvable solids) into the portafilter, but also provides the resistance needed for the hot water to forcefully extract the crema and volatiles in such a short brew time.
Like espresso machines, capsule and pod coffee makers also use pressure to extract the coffee’s flavor and volatiles. Densified coffee in pods and capsules provides an optimal amount of resistance for the pressurized water to extract the dissolvable solids of the grounds.
The result is the consumer enjoys a better cup of coffee.
After coffee is ground by the top section, it takes on a static charge, which, along with the help of the coffee oils, causes it to stick on the inside surfaces of the roll chamber. Gravity is what makes the coffee fall into the subsequent rolls, however not consistently—at least not without the help of the Black Ice Deflectors.
Without these deflectors, coffee accumulates like snowpacks on the internal surfaces and then falls like an avalanche. These avalanches are hard spikes of resistance detrimental to rolls, components, and motors. The sheering function of the rolls suffers when the rush of coffee forces its way between the rolls leading to crushing, which is not good for achieving accurate particle size distributions. Some manufacturers answer the problem by having chains inside each chamber that slide across angled deflectors. But this is a purely mechanical approach not favored by MPE because while chains manage the problem, they do not solve it. Coffee particles still accumulate like snowpacks waiting for the next chain sweep, merely dividing up the avalanche into many smaller ones.
How MPE’s Superior Approach Solves the Problem
The approach favored by MPE is a two-fold solution. First, a vibration device behind each panel renders the entire surface unstable and virtually impossible to stick to. Secondly, application of a food-grade non-stick Black Ice coating on the deflectors helps transient particles in their downward slide into lower chambers. This two-prong approach achieves a consistent rate of coffee always falling into subsequent rolls to eliminate torque spikes and achieve the most accurate particle size distributions.
Granulizer rolls, journals, and bearings are designed for precision grinding in large volumes. With applications requiring tight particle distributions and roll gaps as small as 50 microns, stabilizing tolerances and controlling temperature can make all the difference between a great coffee product and an inferior one.
Heat alters tolerances and contributes to faster mechanical wear. Heat on just a single bearing can throw off the parallelity of the rolls and significantly alter particle distributions and reduce overall precision.
To control the heat of the components, one of MPE’s signature engineering designs is genuine thru-water cooled rolls found on most IMD models. The idea is simple; running water through both sets of bearings and journals—and rolls of course—so that they stay a consistent temperature during operation. This two-sided coolingkeeps the rolls in perfect parallel operation and reduces component wear.
Water-cooling design seen on competitors’ industrial coffee grinders are usually one-sided. And while this may adequately cool the rolls and prevent an undesired 2nd roast of the coffee, non-cooled bearings on the other side are liable to increased heat-related wear and metallurgical expansion leading to a loss of roll parallelity. This loss results in a less precise grind, and consequently, a lower quality ground coffee product.
MPE announces the Gemini Series Model IMD 779.2 Coffee Capsule Granulizer with variable roll speed ratios for achieving the strongest particle size distribution for coffee pods, pads, and capsules. The Gemini has Independent Motor Drives for each roll, allowing customizable roll speed ratios ranging from 1:1 to 1:4 to yield particle size distribution differentials engineered for each application. Its automated recipe-driven control system provides the repeatability of all parameters and grind characteristics. The Gemini is the pinnacle of precision capsule grinding equipment and ultimate grind control.
We are very happy when the work of our customer Green Mountain Coffee is featured on a TV show as fun and exciting as Unwrapped 2.0; but we’re especially proud when the work of our engineering, sales, and manufacturing teams is featured so prominently as well. And in case you were wondering, those are 5″ Chain-Veys (featured at 0:45 and 1:15) and IMD-999 grinders (at 2:25) inside Green Mountain’s roastery.
Let’s talk oxygen. Oxygen’s penchant for stealing electrons gives it a sort of criminal reputation among chemists and MPE engineers. Coffee like any chemically organic matter is inherently delicate and an easy target for oxygen bandits which will chip away at your freshly roasted coffee’s delicate chemical beauty, leaving your coffee stale and with less aromatics. From the roaster to the grinding to the packaging, MPE can implement oxygen free conveyance systems, grinders, and degassing bins. This is achieved by pumping nitrogen, a relatively inert gas, into the system to prevent oxygen from stealing electrons from your coffee (oxidation). Additionally, this can be done in a cost effective way because Chain-Vey is already a significantly more efficient system by design than a comparable pneumatic tube system. An entire post-roaster oxygen free system will improve your coffee’s freshness and aroma making your customers happier. And happier customers lead to more business. Take our word for it.
[The coffee roaster] also knows that the coffee will be brewed and served to customers without the benefit of [his or her] guidance or control. Thus, the quality of the grind must be as constant as the function of the processing equipment.
Modern Process Equipment was the first company to produce a modern Turkish coffee grinder in the mid 90s. Today, they produce around 90 per cent of the world’s industrial Turkish coffee grinders.
Daniel Ephraim, President of MPE, points out that no coffee trend requires greater precision than Turkish coffee grinding. In this front, MPE carries a strong standing, as the first company to build an industrial Turkish coffee grinder using modern technology 18 years ago.
“That really started a revolution,” says Ephraim. He notes that MPE currently produces around 90 per cent of the world’s industrial Turkish coffee grinders.
The main challenge in grinding Turkish coffee, Ephraim explains, is that every coffee bean must be divided into around 30,000 particles. Since MPE’s machines can grind at a capacity of 1000 kilograms of coffee an hour, this equates to an astounding 145 billion particles an hour.
“Because Turkish coffee is put directly into the water, of those billions of particles, we need to ensure there is not even one that is oversized, or it will float and result in a poor brew,” says Ephraim. “That’s a pretty big challenge.”
The advent of single-serve has posed an additional challenge to coffee roasters everywhere looking to take advantage of the fastest growing segment of the industry. Scott Will, Director of Sales for MPE, says that the refinement of single-serve systems, in terms of short brewing times and less coffee needed to brew each cup, has further limited the “room for error” in the grinding process.
“It’s the difference between walking on a tightrope versus an open sidewalk,” says Will. “You have to be perfect in your execution in grinding. You’re dealing with exact brewing times and very small amounts of coffee in a fixed volume at high density. Everything has to line up perfectly.”
For this purpose, MPE has pioneered the patented ‘Vortex’ Normalizer. This device is able to increase the density of ground coffee by 100 per cent more than it’s normal capabilities. This means that capsule manufacturers can increase the strength of a brew – for instance, to brew espresso – without increasing the capsule size.
[This post is an excerpt of a promotional article originally published in Global Coffee Review in April of 2013]