CO2 Reservoir For Cold Crashing

>> Tuesday, January 14, 2020



Today I have a quick little write-up about my CO2 reservoir that I've been using. I got the idea from a kit sold by Brewhardware.com which may have been inspired by a Brulosophy post...I'm really not sure which one of these two came first, but I saw the Brewhardware kit first. The concept is simple, in order to minimize oxygen exposure (e.g. via suck back), employ a reservoir filled with CO2 so that as the finished beer cools and the gas reduces in volume, CO2 is drawn into the fermenter rather than air. As most brewers know, oxygen + finished beer = stale oxidized flavors and aromas, muted hop character, etc.

My first test setup utilized a mylar balloon for the reservoir as described in the Brulosophy post. Mine consisted of a balloon, a small piece of 1/2" stainless tubing jammed into balloon's valve, then this assembly was filled with CO2 and inserted into the fermenter bung. It worked great, but since I couldn't see inside the mylar balloon to make sure it was clean, I started to worry about the potential for infections with re-use. Mylar balloons are cheap, but I didn't want to add one to the landfill every time I brewed a new beer.

This led to my slightly improved second iteration which involved a water bladder I purchased through Amazon. The bladder is similar to Camelbak bladders except it has a slide lock that I can use to access the interior. I also replaced the 1/2" stainless tubing with a 3/8" stainless barbed elbow (because these fit better in the bung). This setup worked well and the only problem was when it was time to transfer to keg, I had to disconnect the reservoir, then connect low pressure CO2 to complete the transfer. Depending on how much CO2 was left in the reservoir, there was the potential to introduce some oxygen when swapping out the reservoir for the CO2 line. Also, I found it hard to maintain constant low pressure CO2 flowing into the fermenter as the beer filled the keg.

Enter version 3 of my CO2 reservoir, and what I think will probably be the final iteration. For this version, I swapped the 3/8" barbed elbow for a 3/8" barbed tee. One barbed port gets inserted into the bung, the bladder is attached to another, and a valved disconnect is attached to the third. This allows me to fill or re-fill the reservoir via the valved disconnect whenever the reservoir is running low. I can also fill it as I'm transferring to keg, eliminating the risk of over-pressurizing the fermenter.

Here are a list of parts I used for my build:

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Bierstadt Lagerhaus Slow Pour Pilsner

>> Sunday, January 12, 2020

Today will be the first attempt trying to clone a beer from Bierstadt Lagerhaus. Bierstadt is located in Denver, Colorado, and it's become one of my favorite places to visit when I'm in town. Besides having great beers, Bierstadt Lagerhaus at The Rackhouse, is just a really fun place to hang out. There are giant versions of games like Cornhole, Beer Pong, and Connect Four, and the food offerings are solid. The Rackhouse also features a full bar plus local ciders, so there should be plenty of options even if everyone in your party doesn't love beer as much as you do.


I first tried Slow Pour Pilsner (SPP) on a trip to Denver in December 2018 on the recommendation of a buddy of mine that had visited during GABF week. On a different visit, they were serving a Smoked Helles. Chatting with our server, he explained how they cold-smoked the grain themselves for this batch. Having smoked my own grain for several of my homebrews, it made me appreciate it that much more. As for SPP, it's just a great example of a German Pils...crisp, clean, and super drinkable, while showcasing traditional ingredients and processes.

The recipe comes directly from Bill Eye and Ashleigh Carter of Bierstadt via BYO magazine. One note, it seems there was a correction to the BYO recipe with respect to the hopping schedule. If you compare my recipe below with the online BYO version, you'll see some differences. I also decided to incorporate a diacetyl rest even though the BYO recipe does not mention one. Other differences include some of my standard practices like BrewTan B, BCAA, and whirlfloc.

Target OG: 1.047
Target FG: 1.012
IBU: 33

9.0# Weyermann Bohemian Floor Malted Pilsner
0.5# Weyermann Acidulated Malt
1.0g BrewTan B (dissolved in warm water, mash)
28.3g Hallertau Mittelfrüh (FWH), 3.1% AA
56.6g Hallertau Mittelfrüh (70 min) 3.1% AA
42.44g Hallertau Mittelfrüh (5 min) 3.1% AA
Wyeast Nutrient
4.66g BCAA (Dissolved in water or wort, 5 min)
0.5 Whirlfloc
(2) Saflager W-34/70 in 2L Starter

The mash for this beer is somewhat complicated, employing both a step mash as well as a decoction. As such, I wouldn't really recommend this recipe for beginners.
  • The first step is a protein rest @131F for 10 min.
  • The second step is @144F for 30 min.
  • The third step is @160F for 40 min.
  • Finally, pull a 1/3 decoction (thin), bring to a boil, and boil for 10 min.
  • Return decoction to main mash and vorlauf until clear.
  • Collect about 4.5 - 4.75 gallons, then top up to a boil volume of 6.75 gallons.
90 min boil, chill to 47F, pitch yeast. Ferment at 47F. Perform diacetyl rest when gravity ~1.017.

Water Profile - To 10 gallons of RO water add:
3.8g Gypsum
3.2g Epsom Salts
4.9g Calcium Chloride

Brewing Notes
I ran into a couple issues with an almost stuck mash. I got a Blichmann Riptide upgrade kit for my March brew pump, and this was the first time using it. I love this upgrade kit, but it seems to have much higher output than the old pump head, as it seemed to be compacting the grain bed. I ended up adding rice hulls and swapping out for my Little Giant pump. I'll need to play around with the Blichmann head a bit. I also think my crush was too fine, so I'll be double-checking the mill gap as well.

The nearly stuck sparge continued to be a problem my Little Giant pump as well, so I think it's definitely related to the crush. Checked the gap and it was too tight, so I dialed it back to .045". I knew I'd adjusted it down for a previous batch, but apparently I forgot to open it back up. Long story short, I got a lot more flour than I wanted. 

No other issues other that I forgot to adjust the grain bill to account for my efficiency, so OG came in a bit high at 1.057.  

Slow Pour Method Details
As the name implies, when you order this beer at Bierstadt, they perform a traditional slow pour. This means it takes at least 5 minutes between the time you order your beer before it shows up; longer if you visit during GABF, but the good news is they usually have a dedicated pourer behind the bar at times like this. The slow pour method is said to improve flavor of the beer, helping to release aromatics and rounding bitterness. You should be serving it in a straight-sided tall-ish beer-clean glass. 
  1. Hold the glass upright under the beer faucet, open the tap, pouring the beer directly into the center of the glass. Stop in time so that the glass is about 1/3 beer and 2/3 head, and before it overflows.
  2. Allow the head to dissipate by about half its original volume. This will probably take around two to three minutes. Open the tap again and stop in time that the head just rises above the top off the glass.
  3. Allow the head to dissipate again for a minute or two. Open the tap one last time allowing the glass to fill so that the dense mousse-like head is about 1/2 to 1 inch above the top of the glass.
Start to finish, the slow pour should take 5-7 minutes to complete. It's pretty common to overflow the glass on the initial pour, so don't get discouraged and maybe keep a towel handy for cleanup. You can also do this method with bottled or canned beer by pouring directly into the center off the glass.

Update 1/13/2020
The wort was down to pitching temps last night, but after a day of brewing plus filling a barrel (Flanders Red Solera), I was pooped. I went ahead and aerated and pitched this morning.

Update 1/14/2020
24 hours in and fermentation has taken off. Per Tilt, gravity it's down to 1.052 this morning. Granted, this may not be 100% accurate as the Tilt can wobble a bit under active fermentation conditions, but it's great for showing trends.

Update 1/15/2020
Gravity reading is down to ~1.045 this morning, so things are progressing right along.

Update 1/16/2020
Gravity it's down to ~1.038 this morning.

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