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Our Brewing Process

Blending tradition with technology, Mendocino Brewing Company strives to produce world class beer at our landmark facility in the City of Ukiah, Mendocino County, California.

MBC’s long history in craft brewing (since 1983) assures that our suppliers understand the exact tolerances that we require of our ingredients.   Our Quality Assurance/Quality Control department monitors both raw materials arriving at the facility and finished products shipping out.  At the heart of QA/QC lies sensory evaluation, as the human palate is recognized as the most sensitive and accurate piece of equipment for testing final product.  Using spectrophotometer, CO2 meter, hydrometer, centrifuge, microscope, nose and tongue, recipes must be periodically revisited and reworked as materials change.  This is where quality meets quality control, where the art meets the science and the Legendary beer is born.

Strictly speaking, beer is made of water, barley, yeast and hops.  With these four ingredients, an uncountable number of beers have been made by innumerate brewers, over hundreds of years.  Prior to the popularization of hops, beer-like beverages date back even thousands of years.  We’ll tackle these materials one at a time here in our own little Brewing 101.



Prior to brew day, recipes are formulated based on style guidelines.  These recipes direct the brewer to “Mill In” a large volume of Pale Malt (most typical for ales).  Pale malt is the canvass upon which the profile of the beer will be painted.  The further additions of “Specialty Malts” are what give each label their own character.  The Maltster, another artisan, roasts raw barley to different degrees to yield different flavor profiles, from sweet to burnt, from notes of raisins to tones of chocolate, any number of these unique malts are blended to deliver the desired color, flavor, and not least, alcohol content.


Prior to brewing, these malts are “Milled In” to expose the available starches (just like the content of a chocolate covered malt ball). The object is to just crack the grain, leaving the hull relatively intact as these hulls will keep the mash porous and will act as a type of filter.  This is only one of the reasons that barley proven itself the best grain for brewing.



Sugar is required for all types of fermentation.  Beer, wine, sake and spirits all share one thing in common, the necessity  of sugar for fermentation into alcohol. The inside of a grain of malted barley contains starches.  These starches will need to be broken down into short sugar chains for good fermentation.  On brew day, the brewer will drop in over 5000 pounds of grain mixed with approximately 2500 gallons of hot water into the “Mash Tun”, a large vessel with a type of propeller in the bottom.  This hot water, and a slow rotation causes enzymes (amylase, just like in your mouth) stored in the barley, to break these starches to short chain sugars.  The temperature is increased for a second similar reaction.  The result is a mixture of barley and water, roughly the consistency of oatmeal, rich in sugars.  We’re now ready to ship to the “Lauter Tun”.



After starch conversion, it’s time for the mixture of grain and water to ship to the “Lauter Tun”.  Once the entire volume of mash arrives, the liquid begins to drain through fine screens in the bottom of the vessel and is pumped to the “Brew Kettle”.  This process is aided by the slow turn of giant stainless steel rakes that can be raised and lowered through the grain bed.  Left behind are the grain hulls which act as a filter for proteins and other particulate matter.  The grain is additionally rinsed or “sparged” with more hot water, until the sugars have been depleted.  At this point, the “Grainout” occurs, that is, the drained grain, or spent malt, is shipped to an outdoor silo.  The grain at MBC is picked up by local ranchers to be used as acceptable filler (only the hulls and a bit of protein remain) for grass fed cattle.  The beef produced is reputed to be some of the finest on the international market.



The raw sugary liquid drawn from the barley is known by brewers as wort.  Each kettle fill is approximately 3100 gallons of raw wort that must be boiled; 60 minutes for lighter styles, 90 minutes for stronger ales, and hours upon hours for some of our Imperial styles.  Boiling wort accomplishes the following: The coagulation of protein for good fermentation and clarity, concentration of sugars in stronger styles, pasteurization of the raw wort, and for the utilization of hop oils…



Hops are blossoms, or cones, that grow on a vine.  On these blossoms are oils known as laupulins. These oils are used for “bittering” the wort which, unhopped, is intolerably sweet.  “Bitter” is to beer what “Dry” is to wine.  This bitterness creates a clean crisp finish.  Later on in the boil, flavor and aroma hops are added.  Some of our styles are “dry hopped” meaning raw hops are added to finished beer to preserve the full flowery aromas of the hops in the finished product.  A little bit of hops go a long way; beer requires tons of grain, but pounds of hops.  For ages, hops have been recognized for their natural capacity as a preservative and as a digestive aid.



Upon completion of boil, the wort is “castout” to the “Whirlpool”.  On its way, our whole leaf hops are removed by our hop strainer.  The hot wort volleys around the edge of a tank creating a whirlpool that forces proteins (and other solids) to coagulate and draw to the center of the tank (“brewfu” if you will). After 10 minutes rest, the wort is siphoned off and sent to the “Heat Exchange”.



The wort is pumped to the Heat Exchange which uses chilled water to cool the wort to 65 for ales, and cooler temperatures for our specialty Lagers.  This must be done so that the hot wort doesn’t kill the yeast on its arrival in the Fermentation Tank.  At Mendocino Brewing, we manage our own proprietary strain of yeast in our lab, which reproduces in such volumes that we always have plenty on hand for tank-to-tank pitching.



Think of ale yeast this way, when the wort arrives, there’s an epic party.   Lots of feasting, mingling about and reproducing.  Ale yeast ferments at the top of and in solution, only settling out when the party is over (after 5-7 days most of the sugars are converted to alcohol).  This huge blowout creates the fruity, nutty and other flavors and aromas distinct to ales. The beer will relax in the tank at 33F for an additional 7-10 days, mopping up off flavors and creating a more smooth, “round” profile.

Lager yeast tends to be more workmanlike.  These yeasts remain on the bottom of the fermentation tank and slowly and methodically consume sugars over a much longer period (3-4 weeks).  Lagers tend to come off drier and with a more subtle complexity than ales.  Lager yeast doesn’t tend to leave much behind besides alcohol.  Proper conditioning at 30F (alcohol content prevents freezing) will allow the lager yeast to reabsorb the sulphury and grassy aromas that are present early in fermentation.



Mendocino Brewing currently uses both diatomaceous earth filtration (think oversized pool filter), and pad filtration (think oversized coffee filter) to achieve clarity without stripping character.  At this point, we could artificially carbonate and package, but what fun would that be…?



Our standard labels, Red Tail Ale, Eye of the Hawk Select Ale, White Hawk IPA, Blue Heron Pale ale, and Black Hawk Stout are scrubbed and carbonated slightly by blowing CO2 through a “carb stone” (a stainless steel tube with microscopic holes in it) at pressure (see Law of Partial Pressure in your high school science book).  The rest of the carbonation, however is achieved by re-introducing a small amount of yeast and sugar to the beer just before bottling. This is known as “Priming”.  More than just being a traditional way to finish carbonation, the yeast will help pick up oxygen (big enemy of beer) in the bottle and dramatically extending the shelf life particularly when stored or shelved warm (known as “Bottle Conditioning”).  It’s our insurance against damage when the product is out of our hands.



We do, and if you’ve read this far, you do too.  Mendocino Brewing is proud to present to you our traditional lineup of original labels, as well as our Seasonal and Imperial Collection labels which are aggressive interpretations of both time honored and modern styles.  Enough reading, raise a glass, here’s to you!

-Your buddy at the bar.

Brew House

Our Brewery

Brew House Hops Barley Lauter Tun Fermentation Tanks Fermenters Bottling Line Warehouse Red Tail Truck

Brew House



Lauter Tun

Fermentation Tanks



Red Tail Truck

Bottling Line