All Grain Mash voodoo... now this is super secret stuff... so don't go blabbing about it everywhere...

The most common questions new brewers ask on this blog and when I'm teaching all grain are... how do I mash... and when is the mash done... and should i stir the mash?  and what the heck is a sparge...

PS - the secret technique is toward the bottom, so keep reading.

These concepts are fundamental to all grain brewing, and partial mash brewing.  So, I'll try to handle them here without too much complication. As you know I hate complications.   We won't be covering multi step or decoction in this post.

Mashing is soaking grains.  Grains that have been malted.

Wikipedia  - close enough for beginners. 

Some Hipster making floor malted barley

"Malt is germinated cereal grains that have been dried in a process known as "malting". The grains are made to germinate by soaking in water, and are then halted from germinating further by drying with hot air.^[1][2][3][4] By malting grains, the enzymes are developed that are required for modifying the grain's starches into sugars, including the monosaccharide glucose, the disaccharide maltose, the trisaccharide maltotriose, and higher sugars called maltodextrines. It also develops other enzymes, such as proteases, which break down the proteins in the grain into forms that can be used by yeast. Malt also contains small amounts of other sugars, such as sucrose and fructose, which are not products of starch modification but were already in the grain."   Pretty darn good explanation from Wikipedia.

Diagram of 2 Row Malted Barley

So we use Malted base grains when we mash.   Malted base grains have enzymes in them.   The enzymes can convert the starches to sugars in a process called Mashing. 

There are really only 3 general types of grains.  Base grains, adjunct malts, and non malted grains.   That is it.   Yes there are hundreds of types of grains, but I think even the worst Tommy Knowitall would agree that all grains fit nicely into one of these categories.   Base grains have enough enzymatic power to convert their own starches and often additional starches.  Adjunct grains do not have enough enzymatic power to convert their own starches.   Other grains may or may not contribute sugars to the wort, but always contribute flavors and color.   That is the simply explanation.  Yes, it can be way more complicated, but doesn't need to be in order to brew great beer.  

Brew in a Bag - Mashing away!

When we brew beer, we soak the malted grains in water.  This makes the enzymes active.   We use specific temperatures to get specific enzymes more active.  We generally soak grains at 140-160 degrees F. (60 - 71 C).   At lower temperatures beta amylase is more active, at higher temperatures alpha amylase is more active.   In general we mash around 150 to 155.  (higher for thicker bodied beers, lower for thinner bodied beers ).   We use 1.25 to 2.33 quarts per pound of grain, depending upon whether or not we are sparging (rinsing) the grains. Sparging is just rinsing the grains.   I generally don't sparge, but you may choose to.  I generally use the grains and make a second batch of beer...That's all there is to this.   If you can make oat meal you can make all grain beer. 

But one question remains unanswered... how long do I mash.   Here is the real secret.  Ok, hold on a minute, before I tell you make sure no one is around.  This is the super secret I mentioned above.   This knowledge will dramatically improve your beer... Brewing is cooking. 

The mash has to take what ever time it takes.  Generally people mash for 60 minutes.  But that is completely unnecessary, the grains and enzymes don't know they are being mashed.  They simply react the way nature designed them to react.   Most mashes convert in 20 to 30 minutes.  If you do an iodine test, you will find that the starches are all sugars.   So, why do we mash longer?  Well experts at Briess  (specifically Aaron Hyde, the product line manager) explains it this way...

What it comes down to - basic starch is converted into sugar.  The simple sugars are converted first, these are shorter chain sugars, so the flavor isn't as complex, thus sweet.  The complex sugar, which takes longer to create is more flavorful, and thus you get more biscuit and nut flavor.  This is also from flavors leaching over time from the grain- the malting process creates melanoidins, the grain contains proteins and other compounds, and they all contribute to this more complex flavor.
So it comes down to simple sugar creation first, and melanoidins and complex sugars coming out later.

So the longer mash isn't necessarily for creation of sugar, although it will keep grabbing more starch and converting it.  The longer mash is to get that nutty, bready, melanoidin taste that comes out of the grains.   How do you know when that taste is there?

Here is the shocker... taste your
mash.   The guys I brew with and I taste the mash every 15 minutes when we stir the mash. Trust me you will know when the melanoidins have leached out. The taste will go from sweet and cloying to nutty delicious bread.  So best advice, taste your mash.   You'll have one of those "aha" moments somewhere later in the mash.