The time has come.
It is time to go all-grain. I’ve got my mash/lauter tun (MLT), my false bottom, my stainless steel valves, my high-temp silicone tubing, my mash paddle, and a good thermometer.
But here’s the thing: I can’t formulate recipes until I know the efficiency of my MLT. Basically, when you mash, you stew the malted grain in hot water, converting the starches to fermentable and unfermentable sugars. When you measure the amount of sugars in the resulting extract (sweet wort) you get it’s specific gravity, which is its density (water @ 60° F = 1.000). Different malts will have varying potential extract, but efficiency is never 100%. In order to hit a target gravity for a recipe, I need to know how much malt to use based on my personal efficiency. I’m hoping for at least 75%, but my false bottom is renowned for its efficiency so I might very well get it in the 80’s.
A couple things affect mash efficiency:
- Temperature: Single-infusion conversion mashes are generally conducted in the 150’s° F. The lower on that range, the more fermentable sugars you’ll get resulting in higher efficiency and higher yeast attenuation (more alcohol); however, you’ll get less unfermentable sugars which would give a beer body. You also want to sparge (rinse) the grains at about 170°, to pull off the sugars, after raising the temperature of the mash to meet it there (“mashing out”).
- Time: A good conversion rest for an infusion-mash should be 45+ minutes. Less time, less conversion. But efficiency is also affected by the length of your sparge. Sparging also makes up much of the volume of liquid you intend to boil. You want to take your time with sparging, 40+ minutes to drain, say, five or six gallons. Patience.
- Manifold: As I mentioned, my false bottom is touted for efficiency. Other popular solutions include cpvc pipe, copper pipe, pie tins, etc.
The false bottom I will be using is fairly similar to those used by professional breweries,except the liquid has to flow up tomeet the valve, where a professional brewery would have it drain straight down and be pumped, through tubes, into the brew kettle.
The false bottom design allows even draining. The positioning of slotted pipes must be considered carefully to allow for maximum flow and evenness. Pipes and braids simply make more sense for rectangular MLT’s only. See this guide on “Tun Geometry and Flow Potential” from John Palmer’s “How to Brew.”
A quick example of where efficiency comes to play in recipes (Note: a gravity of 1.036 = 36 Gravity Units (GU)):
The potential extract for the pale malt you are using is 36 GU per pound, in one gallon of water. An efficiency test of your system results in 75%. That means that you will only get 27 GU per pound per gallon. Therefore you will need 33% more grain to get you to your desired gravity. If your gravity is off, you will have to fix it (adding more fermentables, for example), or adjust the balance of hops to offset the change in expected gravity.
Because I want to know my efficiency, I am going to mash 10 pounds of a single malt, one worthy to act on its own as a base-malt and stand proud without any addition of specialty malts: American two-row pale malt. Even an efficiency in the 60’s would give me a wort worthy of boiling and fermenting, so why waste it? I’ve decided to compliment the single-malt with a single-hop:
Galena, of which I recently scored a cache from the Dock Street brewpub. Galena was developed in the late 60’s as Brewer’s Gold that was openly pollinated (free love, man) in Idaho. It was once one of the most widely grown hops. The water will be straight Philly tap and the yeast, you guessed it, 1056 American Ale.
After the mash I calculated my efficiency to be between 67% and 75%, depending on the specific potential of the malt, which could be between 34 and 38 GUs per pound per gallon. It’s not a bad efficiency, but I could have definitely done a better job of mashing out closer to 170° F, perhaps upping my efficiency into the 80s.
In a month in a half “Straight Shooter: All-American Free Love” will be ready to drink.