Search This Blog

Thursday, August 9, 2012

Getting and Keeping it cool

Getting it cool:
Extract brewers or All Grain brewers, beginning or advanced, everyone has to get their wort cooled after the boil and keep it cool during fermentation.  What are the different methods? Is one way better than another? In this blog post, we’ll cover all this and more.
There are several ways to cool your wort down at the end of the boil. Some ways require almost no extra equipment but take a lot longer to achieve pitching temperature. The most basic of way is the good old Ice Bath.
  This method is what most first time and beginning brewers use. Placing the kettle in the sink or tub filled with cool water and lots of ice.  When I use an ice bath I prefer to hold off on the ice and use cold water to take the initial heat away. This means I fill and empty the sink 3 or 4 times before finally adding in ice. Secondly, I keep stirring the ice water around the kettle and stir the wort in the kettle. This way the heat is more quickly removed.   Of course, this method still takes some time, usually 30 to 45 minutes and the goal is to chill as quickly as possible.
One of the first upgrades any brewer should do is buying a device to achieve better wort cooling. Not only does cooling quicker help keep the beer from getting infected, but quick cooling helps achieve a clearer beer. The cheapest and easiest is an immersion chiller. This is a large copper coil that you can either attach to the kitchen sink or a garden hose. At 15 minutes until the end of the boil, immerse the coil in the boiling wort. At the end of the boil, run cold water through the coil to quickly cool the wort. This method both inexpensive ( has coils starting at 49$), easy and works well. I achieve pitching temperature in about 20 minutes. The downside of using a coil is that it doesn’t work well for larger batches.
That is where plate chillers and counter-flow chillers come in. A plate chiller is a metal “box” filled with many thin plates. These plates allow hot wort to travel through every other opening with cold water traveling though the others. This means that you chill your wort in the amount of time it takes to get out of the kettle and into the fermenter, just a few minutes in total! You can see why this is the method that the professionals use!
Counter-Flow chillers are a bit of a hybrid between an immersion chiller and a plate chiller. The counter flow is typically two copper coils, one inside the other. Hot wort travels through one, cold water through the other, to achieve pitching temperature in just a minute or two.
The key to using a plate chiller or a counter-flow is to regulate the speed that the wort flows through with a ball valve. Measure the temperature of the wort, as it flows in to the fermenter, and slow it down to get the proper temperature.

Keeping it cool:
Fermentation temp control is critical. Uncontrolled, the fermenter can get as much as 10 degrees above ambient temperature and that is bad news! So, how do you keep this from happening? The easiest and cheapest way is a water bath. Placing your fermenter in the tub or large plastic container with water helps regulate temperature swing. You can add ice, or frozen bottles of water to help keep the temperature down. Also, wrap the fermenter in an old t-shirt or towel and place a fan so that it blows across the fabric. This will wick water off the fabric and keep the temperature down.
One veteran brewer I know does this and it works well. He has four half gallon milk jugs filled with frozen water, two of which are in the water bath with the ferment at any given time. He swaps them out each morning and maintains temps in the low 70s.
While a water bath is cheap and easy, it’s not very precise. To be precise you need a temperature controller and a cooling unit. Temp controllers do not cost much and give you a lot of control. Get an old fridge or freezer at a garage sale or from an online site like Craigslist. Plug the fridge into the temp controller and the controller into the power outlet. These units will turn on the cooling device only when the inside temp gets over the temp you set it at.
A few more pieces get you even better results. Get a thermowell, it’s an air lock with a metal tube that extends into the fermenter. You place the temperature probe in the thermowell and measure actual fermentation temp rather than ambient temperature.  If you don’t have a thermowell, place the temperature probe in a large jar of water for slightly better control than measuring ambient temp.
There are many more commercial products and several very ingenious DIY projects for temp control. One home brewer I know used a small “dorm” fridge and several large sheets of insulating Styrofoam to build a small fermentation chamber. Another home brewer built a large walk in and uses a window AC unit to keep it cool.
Do any of you control fermentation temperatures? Leave a comment and let me know what you do because I’m in a new home now and don’t yet have anything more than my closet for fermenting space. I don’t want to keep the A/C running full blast all summer. I hope to start on this project soon and am looking for ideas!

Ok, now what?
Once you are able to keep fermentation temps down, a whole new world of recipes open up. Light beers like Cream ales and Blonde ales, and lagers like German Bocks are now possible. You may find your yeast don’t work as fast as they used. This is due to a slower growth rate and metabolism at the cooler temperature.  Look at pitching two yeast packs or doing an appropriate sized yeast starter (a future topic we’ll cover soon). Let’s take fermentation control for spin with a Belgian Tripple.

All Grain:
8 lbs European Pils malt, 5 lbs American 2 row, 1 to 2oz noble hop. Tettnang or Hallerttau work well, aim for 25 IBUs.  1 lb sugar. 3 packs of Belgian Ale yeast (I like Abby Ale WLP 530, but any Belgian strain can work well) or appropriate starter (2000mL to 3000mL) O.G. should target around 1.070.
Mash at a low temp, around 149 for 90 min. Boil for 90 min. Add hops at 60 min. Sugar, yeast energizer, and clarifier go in at 15 min. Cool quickly to mid-60s F. and transfer to fermenter.  Ferment in the mid-60s F. for the first day or two and then let warm up to upper 60sF. to low 70sF for the rest of the ferment.
By starting at the cooler temperature you keep the esters (fruity flavors) and phenols (spicy flavors) restrained. By letting it warm up at the end, you help ensure complete fermentation. Finishing gravity should be as close to 1.005 as you can get. It’s not easy, trust me, I’ve had many batches not want to complete out. If you find this the case, try skipping the sugar until you hit active fermentation (high krausen). Then, add the sugar to just enough water to make a syrup like solution. Boil it for 15 min, cool and add to the fermenter. This gets the yeast working on the malt sugar first.
Primary fermentation may take 3 or 4 weeks. Once this is done cold condition for 30 days, cold conditioning is when you age beer at cooler than fermentation temps.  Get the temp down as low as you can without freezing the beer. While the cold conditioning is not totally needed I feel it gives the beer enough time to mellow out a bit. If you want to skip cold conditioning, just let the beer sit in primary for an extra week or two.

This style is pretty hard for extract brewers. Use about 8 to 10 lbs Light malt extract or Pils malt extract. At 10 lbs this will be an O.G. of about 1.060, but any more LME and you may not be able to finish dry enough. I’d give up a bit of initial gravity and be able to hit my target finishing gravity rather than end up with a sticky sweet beer.
Boil time will be 60 minutes. Follow as above for boil schedule and fermentation. I’d high recommend skipping the sugar in the boil and add at high krausen to assist in drying out the beer.

No comments: