Brewing Basics - The Mash 101

2/10/12 EDIT:  I went back and re-read my temperature portion of this post.  And to my dismay, I made the rookie mistake of getting higher vs. lower mash temperature backwards.  As clarification, higher temperature mashes result in a higher final gravity (FG).  This means the final product will be maltier, sweeter, and lower in alcohol than beers made with a lower mash temperature.  I was thinking higher temperature meant higher original gravity (OG), but that would be incorrect.  We assume we are attempting to get the same OG regardless of mash temperature.  This is why lower temperature mashes usually take longer than higher to get the same OG.   I apologize for any confusion.  

One of the most feared steps in the brewing process, The Mash, is also one of the most important.  Beginner brewers normally don't need worry about this step, as they will usually be starting with an extract based recipe. Once the brewer is comfortable with the basic steps of steeping, boiling, cooling, fermenting and bottling, it is not unlikely they will want to go one step further and brew from grains instead of extract.

Here today, I'm going to describe why we as brewers deal with the mash, what happens during the mashing steps and will also describe the process for the most basic of mashes - the  Single Infusion Mash, using a batch sparge.  In future posts, I'll dive deeper into the mash, different styles of mashing.

For the sake of simplicity, we are going to assume that the malt chosen is fully modified.  If the malt is under-modified or if the grain bill contains a large amount of adjuncts, a protein rest step would be needed.  Quickly, a protein rest requires heating your mash originally to 120F and sitting there for about 20 minutes to help break down some needed proteins. 

Why We Mash

An interesting question.  Mashing and sparging are time consuming parts of the brew process and you can brew great beer without using this step.  Also, screwing up on the mash and sparge can have big effects on your beer - too little or too much conversion for your beer style, or just causes head aches (I'm looking at you, stuck sparge). 

So, again, why?  Control.  As a brewer, we like to have as much control over every aspect of the brewing procedure, getting our ingredients closer to the source, and being able to chose how we use them.  There's tons of extracts out there, but through the mash we are making our own extract.  So we have the ability to change it's characteristics. I mentioned above one problem with mashing is if you don't convert the sugars to the mash profile for your brew.  While this can be seen as a bad thing, it's also a great tool - we have (theoretical) control over the conversion profile.  

Moving from beginner extract brewing into mashing can be daunting.  The equipment itself can be mind boggling.  For the beginning masher, I suggest looking at partial mash kits.  These do not get all their fermentables from extract, but some.  You'll use much less grain, so mashing in a large grain bag is very do-able.  Once you've gotten the process down, then you may start looking at all grain brewing.

EDIT/NOTE: I did not mean to imply you cannot do all-grain without a mash tun.  There will be posts here describing all-grain brews made using grain bags. 

So, What Exactly is Mashing?

Simply put, mashing is the act of soaking our grains at specific temperatures for specific amounts of time.  The temperature and time chosen are going to be determined by the profile of beer we are looking to make. There are 4 main variables that will effect the outcome of our mash:

1. Step Temperature
2. Mash Time
3. Mash Thickness
4. PH (I'll just mention it here, but I will not go into detail on this today, save for another post)

The Step Temp, AKA Mash Temp or Infusion Temp (these would all be the same in a single step infusion mash) is probably the most important followed by time then thickness.  

Barley contains a ton of glucose molecules called starches.  These starches hold the key to fermenting.  The starches are made up of long chains.  These starches are not fermentable, they are too big for our little yeast critters to eat (and produce alcohol and CO2).  Interestingly enough, barley contains two (well, we'll focus on the two most important for now) enzymes that do a little magic for us, given the right environment

Alpha-amylase:

This enzyme starts to become active when barley is heated into the upper 140Fs (but not really until the mid 150s).  What Alpha-amylase does is cleave\chop long chains of starches exactly in half.  It will deactivate in the 160s and upper 140s. Higher temperatures result in more use of the Alpha-amylase enzyme and result in a sweeter, maltier final product.

Beta-amylase:

This enzyme becomes active in the mid to upper 140's, and deactivates in the 150's.  I've read that even after it's denatured due to getting too hot (around 155F, I believe) it still does some work in the mash.  Anyway, this enzyme 'nibbles' on the ends of long starches and makes smaller, fermentable sugars. With a lower temperature mash, a longer mash period is usually used.  Lower temp mashes result in a lighter bodied final product. 

Mash Thickness:

The mash thickness, or the grain to water ratio is also a factor.  Usually you want a thicker mash, which will give a better mash efficiency. About 2.5 Gal of water per 10 Lbs of grain is a good  starting point, but can be adjusted for beer profile.

 Mash Period, Strike Temp, The Waiting Game:

So, now that we know all about what's happening in the mash, let's talk about actually doing it.  Here there are a couple of options - I use a Mash Lauder Tun (MLT) that I created, but you could use a grain bag (that's a bit tough for an all grain 5 Gal batch, but it will work for a partial mash EDIT: I Don't know where my mind was when writing this - yes, you can do all grain using grain bags, I've done it many times before.  Having an MLT is just easier and usually more efficient.).

We start by heating water to a calculated temperature.  My "Strike Temperature" is the temperature I hope to raise my grains to.  So, we need to heat up our mash water to a temp that, when added to the grains, will adjust to our defined temp.  Usually the temperature will drop about 15°F, but that depends on your setup (EDIT:Keep records! Although we can fix this by adding water later, if we know how much the temperature drops after mixing our grains and water, then we can adjust our starting mix-in temperature next time).  Once we have our water heated, we slowly mix the grains with the water, about 1/'3 at a time.  If you are using a grain bag, slowly fill it and dunk it in your pot.

After about 10 minutes, we need to check to see if we hit our strike temp.  If we did, great!  If not, depending how far off we are, we can add hot or cold water to adjust.  After that, we wait.  The length of time can be anywhere from 20-60 minutes, depending beer style (remember, temp and time will define what the body of the beer is).  We can do a starch conversion test if we have some iodine.  Grab some wort off the top of the mash (make sure there are no particles, they will throw off the test), mix it with iodine.  If the solution starts to change into a dark purple color, we need to mash longer as we have identified starches.

The Sparge:

The final part of the mash is the sparge.  During the mash, we created a bunch of sugars.  These sugars are sticky guys, so we need to rinse the grains off.  This can be done a few ways, and I will be describing how to batch sparge.  In the future I will describe fly sparging.

After we have converted our sugars, we will heat up our sparge water (volume defined  by recipe, but 3 Gal is pretty close).  First we drain all the liquid out of our mash.  We'll re-introduce the first few gallons back to the mash carefully, as to not upset the grain bed.  Continue doing this until the liquid is particle free.  Once particle free, drain ALL liquid from the tun and collect.  This is our first runnings and the base of our wort.

Next we'll pour our hot 160-180F water (spare water) into the mash tun.  Use about 1/2 of the sparge water.  Stir the grains to knock off any stuck sugars into solution.  Allow the grain to settle for about 10 minutes.  Open the valve and repeat the draining and collection process. Repeat the entire process again with the  remaining 1/2 of the hot liquid.

We'll want to drain fairly slowly (don't fully open the valve).  Draining too fast can create a stuck sparge - the grain bed begins to compress as water flows out, sometimes stopping the flow.  This happens more often when fly sparging.  We don't really want to upset the grain bed once we're flowing liquid through it.  If we're stuck, we can stir the grain bed, but that's a worst case scenario.  Mixing the grain bed will add some tannins, that will impart a flavor.  While this is desirable in some styles, usually we want to reduce this as much as possible.  Also, using hotter sparge water can help mediate sparge issues.  Hotter water tends to help loosen up the sugars. 

The entire sparge process should take no less than 20 minutes.  Longer sparges are fine.

By now, you should have collected some 5.5-6 Gal (for a 5 Gallon batch).  And that's it!  

Now, this is the most basic mash out there (well you could skip the sparge, but that would result in a low efficiency).  I'll be adding more posts about more complex mashing.