EisGersteWein – zweiter Teil

When we last looked in on twenty13 it was starting to freeze at about 22° F and just about ready to be extracted into a 3-gallon corny keg. I dropped the temperature of the beer a bit more, driving for the 18 degrees that my calculations told me would concentrate it enough to achieve 20% abv. It got down to 10° F, so I warmed it back up to between 15 & 16° F. This temp worked out just fine though because the keg-to-keg beer transfer was going to happen outside of the freezer chest. If anything I wanted the beer temp. on transfer day to err on the conservative side. If my yield was less than 2.75 gallons, I knew I could always “water down” the beer to reach 20% abv, but it would be a lot more work if I erred the other way around.

Freezing twenty13 to concentrate the alcohol, residual malt and hops was fairly easy, but it wasn't without a couple minor mishaps. After taking the picture of the keg contents that’s in my previous post, I forgot to repressurize the keg and when the temperature was dropped to 10° F, about 1 quart of slushy beer made its way past the lid o-ring and onto the floor of my freezer chest. It smelled great, but was a sticky mess to clean up.

I used my new Spunding Valve to regulate the transfer rate and to make it a closed transfer to avoid any chance of oxidation. It also kept the recipient keg slightly pressurized which helped minimize the foaming that inevitably happens at the end of transferring a beer in this manner. After transferring the contents from both originating kegs I ended up with only 2.25 gallons. I bounced both kegs a few times to get any trapped liquid moving to the bottom of the keg. Within 5 more minutes I was able to transfer an additional quart. About half an hour after, that I was able to get the final few ounces transferred so my final volume was approx. 2.7 gallons.

Once the transfer was finished, the ice in the keg was white and lacked any malt color. It took another day and a half for the contents of the kegs to completely thaw. There was some color and a little flavor to the fluid that I ended up pouring out. I felt really good about how much concentration I had achieved, but I had yet to test the EisGersteWein twenty13 to confirm I’d achieved my goal.

The original beer had an OG of 1.066 and a FG of 1.018 (5.8 Brix), so the original abv was 6.06%. The freezing would increase the alcohol(abv), residual malt (FG) and hops (IBU’s) about 330% so long as I concentrated the original 9 gallons down to 2.70 to 2.73 gallons. The only empirical measurement I could use in my brewery was measuring the FG after all was said and done. I used my refractometer and it read just over 19.0 My calculated goal was 19.1(5.8 x 3.3) to reach 20.21% abv. Short of using a laboratory to confirm the actual alcohol level, I’d say the goal abv was reached. To validate the beer as a success though, the beer had to pass a taste test too.

I belong to a small group of very committed homebrewers – Tao of Brewing. Most of us have been brewing for over a decade, some of us for nearly two decades, but there are some members who've been brewing for only a few years. Our group was formed to give and receive honest evaluation of our beers that don’t any hold any punches. Honest feedback is the goal so that we all make the best beer possible.  

At the meeting this past Wednesday I served the first samples of twenty13 and my fellow brewers said they tasted:

• Huge London Pride/Fullers ESB malt flavor from yeast esters.
• Bittering and flavor hops there but no hop aroma.
• Balanced malt to hop bitterness.
• Alcohol hidden but hits in aftertaste.
• British, bready, biscuity.
• Honey and chamomile.
• Toffee & medium crystal flavor notes.
• Irish whisky-like flavor notes as it warms.
• Definitely beer-like.
• Can smell alcohol slightly.
• Dry hoppiness lingers in finish.
• Strangely dry for a beer with such a high FG
• Loooooong dry, hoppy finish.
• Final verdict: intense, balanced and awesome!

Again and again, tasters were surprised at the alcohol level and they commented on how well balanced the beer tasted. Many of them lamented on how bad Sink the Bismarck tasted to them. They found that beer to be unbalanced and commented how overbearing the hops were in it. These guys are no shrinking violets when it comes to hops, but they don’t like BrewDog products in the least. In twenty13 I planned for the concentration of the hop bitterness and flavor, but I was truly surprised at how well that aspect of the finished beer came off.

In any case, I’m very proud of this beer and can’t wait to force carbonate & bottle it so I can share it with friends and family…now if I could just find 187 ml BROWN bottles somewhere!

As promised, The Spunding Valve explored:

To Spund is the German term for To Bung, To Close Up or To Seal, not some trendy photo pose that’s the next best thing since Planking. A Spunding Valve is a device that has a Pressure Gauge to show vessel Pressure and a Release Valve to vent excess Pressure from that vessel.

• Spunding, in the brewing sense, refers to the act of closing off a vessel containing beer or wort and allowing Pressure to build inside the liquid.                                - By WortMonger in HomebrewTalk.com

While WortMonger’s definition makes a Spunding Valve sound suspiciously like something involved a case of blue balls, not to worry, it’s actually a good thing.

•  It can be a useful way to naturally carbonate a beer.
•  It can also be used to help transfer carbonated beer from keg to keg without    losing any carbonation.
•  In my case, I used one to vent the Pressure that would build up as I transferred the twenty13 EisGersteWein into a 3-gallon corny keg.

Spunding Valves can also be used to regulate the transfer of beer from one keg to another while under Pressure. While that is a great convenience for my EisGersteWein, it is downright necessary if transferring carbonated beer from one keg to another.

I didn’t want any chance of oxygen coming in contact with my EisGersteWein, so after purging the recipient keg of oxygen with CO2(@10 psi – twice), I wanted to keep its lid sealed. Instead of manually releasing the Pressure in the recipient keg as it built up during the transfer, I decided to make my own Spunding Valve. 

Here are the parts needed to build your own Spunding Valve.

 The Valve and Pressure Gauge were purchased on Amazon.com

WIKA 9767045 Industrial Pressure Gauge, Liquid/Refillable, 

Copper Alloy Wetted Parts…$15.00

Control Devices CR Series Brass Pressure Relief Valve,

 0-100 psi Adjustable Pressure Relief Valve…$9.95

The Pressure Gauge, Relief Valve and most of the brass fittings used ¼” npt thread. the other plumbing fittings (female flare swivel, male flare to male NPT adapter, and NPT tee) were bought at my local hardware store.

While some homebrew shops offer similar Spunding Valves, their Pressure Gauges only go up to 15 psi. I bought a slightly more expensive Pressure Gauge that had a stainless steel body, with a wider psi range and that was also liquid filled. These are sturdier and I plan to use it for future carbonation projects. You can probably buy a basic Pressure Gauge that will suffice for only $5.00 though. Total cost for my Spunding Valve was approx. $40.

To use a Spunding Valve in a keg-to-keg transfer, make sure the recipient kegs is pressurized at a slightly lower pressure than the originating keg so there’s no chance of having anything flow backwards through the transfer lines. Hook up your CO2 tank to the originating keg and purge the transfer line so it is full of beer. Finally, attach the transfer line to the recipient keg. The beer should start flowing immediately. 

Eventually, the pressure will be equalized between the two kegs, so slowly open the Relief Valve until you hear the hiss of CO2 gas escaping so you can regulate the rate of the beer flowing into the recipient keg. Once everything is equalized, the Pressure Gauge should read about 2 to 4 psi lower than the Pressure Gauge on the CO2 tank hooked up to the originating keg.

As the transfer comes to an end, be careful to cut off the flow between the kegs so only liquid gets transferred. Allowing CO2 through the transfer hose will cause foaming in the recipient keg, and oxidation of your beer will happen if any air makes its way through the line. If any beer, or beer foam, makes its way into the Pressure Gauge or Relief Valve, it will be nearly impossible to clean….not that it happened to me or anything.

The Relief Valve I used show it was set to about 25 psi when the Pressure Gauge clearly showed the pressure in the recipient keg was between 8.5 & 9 psi…lesson learned!  – Follow the reading on the Pressure Gauge instead of the reading on the Relief Valve. Heck, you may want to buy an unmarked Relief Valve instead.

As for using a Spunding Valve to capture enough CO2 to pressurize and carbonate a beer in a corny keg…that will have to wait for a future post.