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Jul 28, 2014

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Talking temperatures

By Gregg Smith

When historians research causes of historical episodes they look for precursors which took place long before the event. So it is with brewing. Steps you take hours prior to firing the kettle help with clarification and reduce odd flavors and aromas. Most homebrewers use a brew pot with a capacity of one to one & a half gallons. Actually, this size has an advantage of allowing the brewer to execute a concentrated boil. What advantage? Purists use full sized brewpots and to obtain a variety of desirable results. But there's one special advantage reserved for those with smaller kettles and it begins with refrigerating three to four gallons of water hours before you intend to brew.

Have you ever put a bottle of homebrew in the icebox and upon pulling it out found it hazy? It tastes and smells great but what's causing the haze? It could be a number of things but let's tackle an easy one. To get to the bottom of it requires a trip back to the earlier discussion about malt. Any barley malt you use naturally contains a certain amount of protein and starches. Both these molecules which have a long length and in fact are often referred to as "long chain" molecules. Despite everything taught in school about their small size, long chain molecules are big enough to reflect light, causing homebrewers no end of distress.

How do commercial brewers avoid haze? In part they make use of a filter so small it effectively removes these offensive light reflectors. However, care in brewing can be just as effective and one of the brewer's allies is the malting process which helps break these molecules into shorter lengths. The shorter lengths don't cause haze and have the added benefit of acting as nutrients for yeast. Not with standing the maltster's success, some of these long molecules still make their way to the brewpot. Dealing with these is left to the art of the brewer and now for your weapons in this fight.

Strategy number one is to maintain a good vigorous boil. A vigorous "rolling" boil is desirable for sanitation and infusion of your hops. It also assists in clarifying the beer. Turbulence in the kettle causes the long proteins to bump into each other. The collisions make them stick to each other (coagulate) and they subsequently fall to the kettle's bottom (flocculate). This is often referred to as "hot break".

Another tactic employed during the boil takes place in the last 15 minutes. It is at this point you can add something called Irish Moss. No needless apprehension, this isn't really moss and it won't make your beer moldy. In fact Irish Moss adds no flavor to your beer. Its job is to assist in all the agitation andbumping. It also sticks to any long molecules and then drops out of solution.

Okay you now have a couple of techniques to use during the boil but what about the water in the refrigerator? Don't worry, you'll be using it in a few minutes. When your boil is complete you'll need it to quickly cool the wort. There are advantages to this quick and painless cooling. Aside from clarifying the beer, it sets the temperature at an optimum level for the yeast, and it reduces the possibility of off flavors and aromas.

Can this step be as uncomplicated as the vigorous boil? Sure, when you add your finishing hops turn off the heat and drop the brew pot's lid in place. There's an easy start. Next is even less tricky. Place the pot in the sink and fill the space around the outside of the pot with ice, up to about two inches short of the top. Add tap water to the same level as the ice. This will start the cooling process. Remember the cold water you set aside? Since you're making five gallons you need to add the gallon and a half or so of wort to about three and one half gallons of water to make a total of five gallons in the fermenter. By this point you've no doubt leapt to the logical conclusion of what will be done with the cold water. When the ice melts in the sink remove the pot and dry off the outside. Then pour the wort into the primary. Finally, use the refrigerated water to bring the level in the primary to five gallons. The result is a nice cool mixture of about 70 degrees, perfect for fermentation.

When you took the lid off the pot in the sink you might have noticed wet, fuzzy looking globs floating half submerged in clear ribbons of wort. Congratulations, you secured another piece of the haze free beer puzzle, "cold break". If you didn't notice this in the pot you'll surely see it in the cool fermenter within about fifteen minutes.

Remember minimizing off flavors and aromas? Guess what? You've done a good part of the work. Your beer is most susceptible to off traits, for instance smelling like cooked corn or vegetables (called DMS), during the period it goes from boiling down to the optimum temperature for "pitching" yeast at about 70 - 80 degrees. It is also the time when the wort can be infected by wild airborne bacteria which can thwart all your good brew intentions. However, if you cooled the wort with haste, you took a step toward cleaner tasting and smelling beer.

One last set of considerations for you to mull over. You can ruin everything you've done so far if temperatures aren't maintained at proper levels during fermentation. Ale yeast works best at about 60 to 75oF. Once it rises above 75 degrees it enters the range where fusel oils can be produced, bringing a solvent like aroma to your beer.

In warm weather locations it's very common to be above 70 degrees for much of the year. What's a poor brewer to do? Try putting thefermenter in the north east corner of a basement; it's usually the coolest spot in the house. Don't have a basement? Place it near your air conditioner (and cover it from light). If it's a bit too warm in either the basement or near an air conditioner no problem, wrap a towel around the primary fermenter and place it in a pan of shallow cool water. Natural evaporation will give you an additional 2-4o of cooling. Not yet cool enough? The breeze of a small fan can buy you a couple more degrees. If still too warm you may need to invest in a second-hand refrigerator and modify it with a thermostat kit. Your local shop can make a recommendation on which installation yields best performance and most are easy to install.

Try these easy steps in all your brewing: boil vigorously, add Irish Moss in the last fifteen minutes, quickly cool the wort and maintain proper fermentation temperatures. Both you and your beer will appreciate it. So will I, when you finally offer me one. See you around the brewhouse.

Gregg Smith

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