Saturday, June 26, 2010

An explanation of carbonation

Carbonation is the dissolving of a gaseous carbon dioxide (CO2) in a water based solution, the most important application of this is beer. In beer there are two types of carbonation, natural and forced, both will be covered here. Before delving into carbonation's application in beer products it is important to understand the science behind the process.

Henry's Law

William Henry was an English chemist that lived in the late 18th century. His work with gas analysis lead to the development of what would come to be known as Henry's Law.


p=partial pressure of the gas above the solution (atm)
c= the concentration of the solute (mol/L)
kh=Henry's Constant, : 29.4 for CO2 at 289K (60.53°F) (atm/mol)

Note: kh is actually a changing coefficient that changes rather than a constant. It changes with respect to temperature using this equation: kh = kh,ref Tref.exp(-C.((1/T) - (1/Tref))) This is important when carbonating beer because it will determine how much carbon dioxide get absorbed into the beer.

This relationship tells us that for higher pressures of gas you will get higher concentrations of gas in your solution. This is how the CO2 gets into the beer. Now where does the CO2 come from? There are two different sources for carbon dioxide in beer.

Natural Carbonation

When yeast is put in a solution containing sugar it begins to "eat" causing a chemical reaction producing carbon dioxide and ethanol, two key ingredients in beer creation.
Carbon dioxide is an odorless colorless gas that you exhale when you breathe out. After beer has sat in the secondary and is ready to be transferred to bottles a small amount of priming sugar is added to the solution to help carbonate the beer. During primary and secondary fermentation the CO2 is released through the airlock and into the surrounding air. When bottling there is no place for the CO2 to go so it builds up pressure. And as explained previously when a gas is under pressure over a liquid it is absorbed into said liquid and in our case carbonates the beer.

Forced Carbonation
The process of forced carbonation is very similar to natural but instead of the yeast creating the and the pressurized CO2, a bottle of liquefied gas is used to create the artificial pressure and carbonate the beer.

Dry Ice Carbonation
I have never actually heard of someone doing this with beer but I thought I would put it on here anyway. You can drop a small brick of dry ice (Frozen carbon dioxide) into a sealed container and have it pressurize that way NOT RECOMMENDED because the amount of pressure you get harder to predict and could cause an exploding bottle/keg.

Friday, June 25, 2010

Multi-Body Regulator Installed. Kegerator Complete....?

On Tuesday I received my multi-body regulator and it is going to work out perfectly. I ran into some trouble trying to find space for it though. I had to reorient my kegs so that they are staggered a differently, this way there will be room for 4 kegs, the tank, all regulators and the hoses to fit perfectly. A quick visit to Home Depot got a brass 90° fitting so the gas line would point down to the tank instead of making the hose make the 90° turn.
A stand-off was to be made because collar located the regulator in such a way that the gas lines interfered with the top of the freezer. A 2x4 screwed to the collar gave the correct standoff distance and made mounting the regulators easier to locate.

After closing the lid several times to make sure there was no interferences with my new regulators and the body of the kegerator the only thing left to do was run air to it. I set the pressure gauge on the tank to 30PSI. This will allow me to independently carbonate any of the four kegs at 30 PSI, or to regulate them down to a more drinkable 10 PSI or any intermediate pressure the beer dictates. The Bottled Blonde is a little overcarbonated so i have dropped the pressure down to 7 PSI until the head situation gets under control. I am going to do a write up explaining carbonation and the temperature - pressure relationship later so check back soon for that.

This completes my chest freezer keg conversion... pretty much. There are some small things I still need to do like drill a hole to pass the thermocouple through the kegerator wall so it is not dangling over the edge. I would also like to put casters on the bottom so I can easily move it around. Of course I will be adding 2 additional kegs and tap handles but the cost of this project has been higher than expected. I have put a photos below of the final product. Check back later for more additions and further brewing shenanigans.

Wednesday, June 16, 2010

Tapping into Trouble

I finally have my first keg brewed beer drinkable my Rapist's Wit. However, all is not well in Beeradise. The first pour out of my keg was ridiculously foamy (I filled a pitcher with foam) I quickly realized that it was still on 30PSI so I turned it down to 10 PSI and it flowed much better. The first couple pints out of the keg, after I wasted 2 pints to trub, were piss poor at best. So, I frustratingly stormed off and cried for about an hour.
I actually sat down and pondered why my beer had turned out so poorly and watched a couple episodes of south park. Later in the afternoon I realized that I could put start to carbonate the blonde. This got me in a better mood until I got to the kegerator and realized my grave oversight. I only had one regulator and had two beers in need of differing pressures. Bwa Bwaaa. I did some quick Google recon and discovered that you could put just a little pressure into the drinking Beer while still leaving the other beer on 30 PSI by pressing the disconnect on for a moment and then releasing it. This is about the least accurate way I could think of regulating beer pressure. However, desperate for a quick solution I did it and searched for a better solution.
The best thing I found was a multi-body pressure regulator which would allow me to regulate the pressure of each keg individually. Pleased with my discovery I quickly tried to source one and ran into my next road block. These things are Freaking Expensive. The one at was the cheapest 4 body regulator I could find. I doesn't have check valves built into the line but that is OK because all of my gas valves have one right after the disconnect. So $160 later (shipping) I am on my way to a fully regulated kegerator.

Happy Ending: The next day I decided to return to my crappy beer (suggested name change: Dim-Wit) for one more try I and discovered it had mellowed out and tasted exponentially better. The crisp clean taste with a medium aroma of the orange zests and light coriander was a delight on the semi chilly day. I cant wait to try it on a hot summer day while mowing the lawn. Hopefully my girlfriend will bring it to me and finish mowing. I am reasonably sure I didn't let it sit long enough before drinking.

Monday, June 14, 2010

Tap Handle #2

Today I added the second tap handle in preparation for the Bottled Blonde and realized the first tap handle was unusually cold. I quickly realized this was caused by the shank acting as a heat sink and bringing the cold outside of the refrigerator and wasting energy. This is a problem since one of the major benefits of using a chest freezer for a kegerator is that it is more energy efficient. I had a couple of theories on how to fix this:
  1. Fully insulate the shank so that the cold does not pass through to the outside. The only problem I see with this is that the 6-8 inches of beer in the tap handle will not be as cold causing the beer to foam more and may taste poorly.
  2. Insulate the first part of the shank against the wall leaving the last couple of inches exposed to the cold. Thus increasing the thermal resistance between the outside but not fully insulating it. This would effectively cool the shank but not let as much escape to the outside.
  3. Screw it and believe that the amount of energy is small enough for me to count as negligible.
Since it didn't really cost that much to insulate the shanks I decided to try that. I went to Lowe's and bought a 1" water pipe insulation sleeve and ran it around the threaded shanks (Right). Within an hour I could feel the difference in the temperature of the tap handles. The insulation was definitely working. I wrapped the them in electrical tape so that moisture would not enter the porous insulation and have a mold problem. Though I believe it would be minimal since it is constantly cold, I decided to do it since it electrical tape is cheap and I had some lying around. When I hook up the kegs tomorrow I will find out if I need to cut some off and expose part of the shank or just take them off completely . Ultimately the beer is going to decide the thermal efficiency of this kegerator.

Saturday, June 12, 2010

Busy Brewing Day

I had a very busy brewing day today. Drove to the home brew store looking to buy a keg to transfer the Bottled Blonde but they were out so I had to to come back later after they received a large order in. To my surprise they were blue topped kegs. So I bought a new keg new In and Out for it and a T-splitter so I could add onto my existing setup. Which brings me to my existing setup. I finally have the temperature controller working like I wanted it to so I decided to finally carbonate my Rapist's Wit by putting it on air and in the kegerator (Shown Right). In three days I should be able to drink the Wit. The blonde should be ready to put in the kegerator in three days and then ready to drink an another few days. The first 2 pints out of the keg will be mostly trub so that will just get wasted and poured out. This is about the same amount that would have been wasted if I would have bottled or some other method.

Thursday, June 10, 2010

Recieved my temperature controller today...

Today I received the temperature controller straight from down under. Unfortunately that is all I got, it came with no instructions whatsoever as shown above. There is a wiring diagram on the top of the module but it is not very detailed, but I eventually figured it out. I found a website using the same controller for a chest freezer conversion that was helpful. I also emailed mashmaster for instructions but before they got back to me I found the spec sheet hidden on their site. I don't know exactly where I am going to punch through the wall to put the thermocouple so for now I am laying it over the side of the freezer to make sure the temperature stabilizes before I put my precious beer inside. I used a three wire cable to connect the controller two for power and one to send send the power to the compressor, turning the refrigerator on. I did this so the controller could be mounted remotely and it gave some flexibility. I chose to leave the green light because it tells you the refrigerator has power and I didn't want to have to find something to cover the hole. I thought about putting the screen for the controller there but It would have to be mounted sideways.

Monday, June 7, 2010

Bottled Blonde

Origin:The day of summer are upon us so this weekend I decided to brew a refreshing summer ale. I decided to make a golden/blonde ale and should be just what I need after a hot day mowing the lawn. We have not really had a really hot day yet this summer (Oregon) but this is an anticipatory brew. The name I came up with because the label I envisioned was a buxom bottle blonde that is stuck in a bottle trying to get out, and I also couldn't think of anything clever to call it so Bottled Blonde it is.

  • 6 0z. German CaraHell
  • 4 oz. German Vienna Malt
  • 7 lbs. ExtraLite Malt Extract
  • White Labs California Ale Yeast
  • 2 oz. Cascade Hops (6.0% alpha-acid, whole leaf)
My friend Nick was interested in getting into home brewing so I thought that this would be a good simple introduction to brewing for him. I began with the standard boil of 3 gallons placing the grains in with the water while it climbed to 180F. Once 180 was achieved the grain bag was removed and shortly thereafter the water began to boil. After the boil began I added the Extra Lite Malt Extract and stirred to make sure it did not burn to the bottom of the kettle. The boiling subsided and once it started again I used the following hop schedule:

Quantity Ingredient Boiled for
1 oz. Cascade Entire 60 min. Boil
1/2 oz. Cascade Last 12 min. of boil
1/2 oz. Cascade Last 2 min. of boil
After the completion of the hour boil the hops were strained and sparged into an ice filled bucket. Once the temperature reached 80F I pitched the White Labs California Ale Yeast and placed the lid on the brewing bucket. After this the bucket was placed in what will now be called my "Brewing Closet" with the keg of Rapist's Wit that is waiting to be carbonated.

Tuesday, June 1, 2010

FridgeMate MKII Digital Temperature Controller Kit

So the kegerator is not working exactly like i want it to, the temperature range is wider than I would like and the refrigerator thermostat is not giving me consistent results. So to solve this problem I am going to throw some money at it! YAY! I just bought a FridgeMate MKII Digital Temperature Controller Kit hopefully this will have a more accurate control over the temperature ranges. If you do decide to go this route, be sure to get the 110v version if you are in North America and using a standard plug in freezer. This will leave an unused hole in the kegerator where the old thermostat went but I might be able to put the new controller in there or cover it up. If all else fails I can just leave the non functioning temperature adjustment where it was.
Now I get to wait for the thermostat to get here from Australia. For some reason the only place that I could find this specific thermostat was MashMaster which is an Australian based brewing supply company. Crazy Aussies.