Wednesday, December 12, 2012

All Grain

You probably know by now that brewing beer is very simple and it basically requires a source of sugars to be fermented. The majority of sugar used in brewing are from barley malt, that are available to home brewers in different forms, as malt extract (liquid or dry) or by mashing the barley malt at home to transform the starch within into sugars.
The process which involves only mashing as the main source of sugars is called all grain and briefly describe on this post.
Here are few points that I believe encourage home brewers to move on to all grain:

  • Large variety of malts available, allowing brewers to compose their recipes as they please, making minor adjustments to reach their targets.
  • Possibility of brewing very light beers
  • Cheaper than malt extract brewing, specially when buying base malts in bulk
  • Long term storage of grains allow brewers to avoid repeated trips to brew stores, sometimes located far way or inaccessible during harsh winters.
Note that adding adjuncts like wheat, oats, corn flakes or even sugars like honey, lactose and dextrin would still be considered all grain brewing, as long it doesn't represent a large percentage of the grain bill. I don't think there is a threshold for this.
Anyways, if moving to all grain brewing, the main piece of equipment you will need is a mash tun. you can buy one ready from you LHBS or build one yourself, as many home brewers do. All it takes is a cooler that is about twice the volume of your batches and some easy modifications. The purpose of a mash tun is to hold the barley malt and hot water for about an hour until the proper enzymatic conversion of starches into sugars are achieved. The enzymes are already present in the barley malt and are activated when soaked in hot water from 150 to 160F. Depending on the exact temperature within this range, the sugars created can be of longer or shorter molecule chains. If short, the yeast will be able to easily convert it to alcohol and CO2. if long chain sugar, the yeast will not convert it all and residual sweetness will remain in the beer, which may or may not be appropriate depending on the beer style one is brewing.
Here are few options for a mash tun:
Round Cooler: this is a small 2 gals cooler I modified just for testing. It can be scaled up to a 10gal cooler easily. This is the most popular design I have seen.

The mash tun needs a system to be able to drain the wort and leave the gains behind. Some use a false bottom, some use a ss braid as shown here.

This is the system to re-circulate the wort, so the grain bed tights and allow a clear wort to be drained.

Here's a different cooler setup.

Basically, the all grain process resumes to these steps:
  • Elaborate the recipe and mill the grains. It can be done at home if you have a grain mill, or at your LHBS which usually do not charge anything.
  • Heat water to strike temperature, which is calculated based on the batch size, amount of grains, temperature of the grains and other factors. Basically, you heat water so when you mix the grains it will stabilize on your target mashing temperature (anything you selected between 150 to 160F). There are online tools that include strike water calculators. My toll, developed in excel does that also and can be found here. The tricky thing about striking water calculators though is that it is dependent on factors that are particular to your system, like heat absorption of your cooler walls for example. If you stick with one cooler model and find out that the calculator is 3F off the real deal, you can just offset the results for future brews.

  • Dump the heated water to your mash tun.

  • Mix in the grains 

  • Take a measurement of your real mashing temp. That is right after mixing the grains. Until you dial in your system response it is always advisable to have some boiling and cold water available for last minute adjustments. If you miss the target by too much, let's say you get 145F instead of planned 152F, just add some boiling water in small steps, mixing well and taking new measurement until you reach 152F. Same as if you ended up above the target. Just add cold water to adjust as needed. Again, once you know your system, easy correction can be applied to the striking water calculations to zero in on your target mashing temperature. After 1h and before start re-circulating the wort, take another pick to see how much the temperature dropped. Ideally, you would like as low temp drop as possible. If your mash tun drops more than 5F in 1h, consider improving its insulating capabilities or getting a better cooler.

  • Mash for one hour

  • Re-circulate and drain the wort

  • Sparge, which is nothing more than washing the grains to extract as many sugars as possible. Batch sparging is the most used I believe and what you do is drain all the wort, close the drain and dump hot water at 165F to the grain bed, mixing well. Then re-circulate the wort until it clears and drain it again. Fly sparging what I do and consists on slowly adding hot water (165F) to the top of the mash tun at the same time at the wort is drained, pretty much keeping the level constant. As the heavier sweeter wort is drained from the bottom of the mash tun, clear, lighter and hotter water is add to the top, pushing downwards washing the grains. Once the volume of wort for your batch is achieved, mashing is interrupted and from this point forward the process is exactly the same as extract brewing. You bring the wort to a boil, adding you hops and any other spices/adjuncts as called by the recipe.

 Here's s snapshot of a fly sparging.

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