Monday, November 22, 2010

Some Background Information

Taken from my project proposal....

"The problems I aim to solve with this project are the complications and inefficiencies of the infusion step mash process faced by many home brewers. The first step in brewing beer is the mashing process. This is when the grains are soaked in hot water to allow enzymes to convert the starches into fermentable sugars. While there are different methods of mashing the goal of the home-brewer is to achieve max efficiency and convert as much of the starches into sugars as possible. This will in turn reduce the required grain bill and save money for the brewer.  The most efficient process is known as step mashing.  For this process the grains are added to a certain amount of water at about 100 degrees.  The grains now referred to as “the mash” is then allowed to rest at this temperature for about 15 minutes. This is the also called the acid rest. Next the temperature of the mash is raised to around 122 degrees and allowed to rest again for about 30 minutes this is called the protein rest. Next the mash is raised to 140-150 degrees and rests for 45 minutes. This is the saccharification rest. Finally the mash is raised to 170 degrees and the sugary liquid referred to as wort is drained from the grains and into the boil kettle. The grain bed is now rinsed with 170 degree water in a process called sparging. This water rinses any remaining sugars from the grains and is collected in the boil kettle.
The problem with step mashing for the average homebrewer is achieving accurate temperatures at each step. Many rely on a method called infusion step mashing. This is when a certain measured amount of boiling water is added to the mash to achieve an equilibrium temperature equal to the next desired step temperature. This method is difficult to maintain accurately and involves many adjustments and temperature reading and results in fluctuating temperatures that can be harmful to the enzymes.
For my project I will design a system that will re circulate the wort from the mash tun through a heat exchanger and precisely maintain a set temperature.  The wort will be drawn from the bottom of the grain bed pumped through a coil immersed in the hot liquor tun where it will be heated then pumped back on top of the grain bed.  The entire system will be monitored and controlled from a laptop computer with all temperature steps and rests preprogrammed for the specific beer style.  The temperatures of the system will be monitored at multiple points and used to control relays to turn on or off the heater.  The pumps and valves for wort transfer and sparging will also be controlled by the system. I will need to design methods to monitor water levels and ph levels as well as temperature.  All information will be logged and used to report efficiency of the system and for reference for future use.  " 

During the course of this project I intend to try to explain the brewing process to the best of my knowledge but I'd like to point out that I'm not any sort of expert when it comes to brewing beer. I've been brewing for about 2 years now and probably have about 15 batches under my belt so far and only 4 of those have been all-grain* batches. However it only took me a couple of day long all-grain brew sessions to realize that step infusion mashing as way too much work and frustration.   

*All-grain brewing refers to the process explained above where the home brewer mashes the grains to produce the sweet wort. An easier alternative is extract brewing, where the brewer adds concentrated malt syrup or powder to water and then boils as usual.  Extract brewing is the starting point for most home brewers as it is relatively inexpensive to get started as it requires far less equipment and can be done on the kitchen stove. Extract brewing is fairly simple and can produce excellent beers however it limits the extent of creativity when it comes to selecting different grains.

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