Introduction To Mashing


By John Brady
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Enjoy homebrewing and thinking of taking it to the next level by going with an all grain mash?  Not only does it allow you to control the process and style of beer made to a greater extent than with extract brewing but it’s where a lot of the magic of making beer occurs.  Using malted barley, the starting point that virtually all breweries large and small make beer from, you can make virtually any style, and as good and frequently better than they do.  This is not a strict protocol but a description of the process and why its unique and special for so many homebrewers
But first it’s helpful to know a little about the malting process and why it is done to the barley you start with.

What happens in the Mash

Yeast cannot consume and ferment the complex starches in barley grain until they are broken down into simple sugars like maltose.   Malting is the process of sprouting the barley grain by wetting and allowing it to germinate, then drying and baking it a little to preserve it.  The natural process of germination expresses enzymes in the dormant seed that can convert starches into sugars to fuel the newly developing plant.  Then when a little sprout starts to emerge but before the new plant really starts to grow and consume those starches, the grain is dried with air and gentle heating to stop the plant growth yet preserve the enzymes inside the grain. These enzymes are now ready to go to work when reconstituted and activated with warm water. This grain is called malted barley. It’s a very clever system.  Each grain is an amazing compact packet of complex carbohydrates, proteins and now the enzymes to do the job of making delicious sugars from the starchy grain for whatever we want and in this case, its making Beer!
Here's where more magic happens. Enzymes are amazing proteins that can catalyze chemical transformations such as the breakdown of starches to simple sugars.  Two major enzymes in malted barley are alpha amylase and beta amylase. They work together as alpha breaks the complex carbohydrates into random pieces and beta cleaves the fermentable maltose units off the ends of smaller chains.    Even though these enzymes normally work slowly in nature at lower temperatures helping feed newly germinated seeds grow into plants, after barley has been malted these same enzymes can be sped up greatly by hydrating them at significantly higher temperatures.   Each enzyme has its own temperature and pH for top speed in a mash cleaving up starches into fermentable sugars.  Alpha amylase is best at 158F and beta amylase at 140-149F, but as they are still active at overlapping temperatures you can, for starters, just mash at about 152-156F and a pH of 5.2-5.3 and get the job done well.  Its not hard and you can taste the amazing sweet grainy liquid emerge as the mash progresses.
Milling grain for mash

Why we mill Grain

Before you start your malt is cracked or milled to an average grist size that is small enough to fully access the starchy endosperm but not too fine.  You don’t want the mash set up like a wet dough which liquid can’t flow through. The grist size should be big enough to enable the bed of grain to act as a filter, allowing the dissolved sugars to rinse through but keep the grainy dust and particulates filtered out.
So you fill your mash tun with hot water, add the milled malt, mix, adjust the temperature and and check the pH.  The conversion can happen quite quickly but give it an hour or so and it should be done. 

Performing an Iodine Test

There’s a nifty test to see if the starch conversion is finished using common drug store iodine.  Take about a tablespoon of the liquid from the mash and add a few drops of iodine and mix.  If it turns black there are still starches present and you need more time.  If the color is just a slight tint of iodine, the starches have largely been converted to sugars and you are ready to move on.  
Lautering & Sparging

Lautering & Sparging

Your mash tun has a valve and false bottom of some sort to allow the sugary liquid to drain out the bottom.   You also add more hot water, called sparging, to rinse the dissolved sugars out through the grain bed and into your awaiting brew kettle. When finished if you have a sufficient volume and gravity of sugars in your preboil wort to make the beer you desire, continue with the boil.  If not, no worries, you can add a little liquid or dry malt extract to get where you want to be and call it a “partial mash”, another time-honored method of making great beer.
 Above all, make the beer you want and enjoy the process! Mashing with malted barley grain is a great way to add depth, character and style to your beer whether its 10% or 100% of your sugars.   It’s a fun and satisfying process. Try it!  You will learn more by doing it, and you will like the results.  Cheers!

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