Beer Overboard!

Picture yourself in the kitchen. You’re about to open the first bottle of your latest batch of beer, an amber ale.

Brewing went well, you hit your target gravity, and the wort tasted great when you siphoned it from the fermenter into bottles. You’re rightfully expecting another ringing success.

You pull out your lucky bottle opener, the one with the ceramic bulldog head on the end. You position the bottle between the bulldog’s teeth and pop off the top.

Suddenly, a rising tide of foam spills out of the bottle and over the sides. The bulldog gets wet. Your hands get sticky. The four-color Amber Sunrise label you painstakingly drew with felt-tip pens begins to run. Your long-awaited ale cascades onto the rug.

Okay, it’s not a disaster. There’s still plenty of beer left in the bottle.

You can’t share this batch with your friends, at least without fair warning (more for you—that’s not necessarily bad). But still, you had high hopes for this brew.

Something went wrong, very wrong…

The Natural Way
A distinguishing quality of a fine hand-crafted beer is proper carbonation for its style. While correct carbonation will not turn a marginal beer into a great beer, an otherwise great beer is certainly unappealing if it’s flat or if it bursts out of the bottle onto the floor. With a little care and a good procedure, you can easily create properly carbonated beer—avoiding the problems of both under-carbonation (flat) as well as over-carbonation (the dreaded gusher).

Homebrewers typically carbonate their beer using a process called natural conditioning. Natural conditioning is a secondary fermentation that occurs directly in the bottle or initial keg. The process can begin once the beer has fermented out. Additional fermentable sugar (typically corn sugar) is mixed with the beer just prior to bottling or kegging. This is called priming.

Natural conditioning relies on residual yeast suspended in the beer that didn’t settle out during fermentation. The yeast consumes the priming sugar and releases carbon dioxide. Because the bottle or keg is capped, the carbon dioxide is not able to escape. Over time the trapped carbon dioxide dissolves into the beer, naturally carbonating it. Typically the carbonation process requires two to three weeks to complete.

Priming Procedure
Successful priming requires knowing how much priming sugar is necessary to achieve the proper carbonation for the beer style. In addition the brewer must adhere to a procedure that results in consistent and sanitary priming.

The first step is to pick the ingredients. Several varieties of priming sugars are available to the homebrewer. Corn sugar and malt extract are by far the most common.  However, it is possible to prime with molasses, table sugar, and even honey.

All-malt purists often insist on the use of malt extract over corn sugar for priming. As a practical matter, however, corn sugar is inexpensive and provides consistent results. Corn sugar also has the advantage of being 100 percent fermentable, whereas malt extract is not.

The amount of fermentable sugars in malt extract will vary by brand. Therefore, some amount of experimentation with a specific extract may be required to achieve the desired carbonation.

The box on page 62 depicts typical priming amounts for five-gallon batches to naturally condition beer in bottles. Reduce these priming levels by 50 to 60 percent when kegging. You can use these figures as rules of thumb and make adjustments on subsequent batches.

If you want to be more precise with your priming, you will have to determine the amount of priming sugar necessary to reach a particular volume of CO2. This does involve some math.

Here are the rules: Approximately 3.2 grams of corn sugar will yield one volume of CO2 per liter, a low level of carbonation. Multiply 3.2 grams of sugar by the volumes of carbonation you want in your beer. Then multiply that total by the number of liters of beer you’ve brewed.

For example: If you wanted to achieve 2.5 volumes of carbonation for your five-gallon batch of pale ale, prime with eight grams of sugar per liter (3.2 grams times 2.5 grams per liter). Five gallons contains 18.92 liters, so you will need a total of 151.36 grams of sugar.

Bottle Priming
Bottle priming is the process of adding corn sugar or dried malt extract directly into each bottle prior to filling with beer. Typically, one teaspoon of corn sugar for each 22-ounce bottle is sufficient. A small, sanitized funnel is useful to speed the process.

The advantages of bottle priming are that it is relatively fast and it enables you to rack directly from the secondary fermenter into the bottles. The disadvantages are that it is difficult to achieve consistent results between bottles, and it is difficult to maintain sanitation.

Many homebrewers who keg their beer will often bottle prime two or three bottles from each batch. They are then able to give the beer to friends or easily transport the beer to parties. While bottle priming is certainly effective, most homebrewers prefer batch priming.

Batch Priming
Batch priming involves adding a sugar syrup to the entire batch of beer prior to bottling or kegging. Batch priming has many advantages over bottle priming. The process is more sanitary and because the priming sugar is syrup, the beer is better able to mix with the sugar. Therefore, results are more consistent with little chance of contamination.

Here’s how to batch prime five gallons of beer:

  1. Once fermentation is complete, rack (siphon) the beer into a sanitized bottling bucket. A six-gallon food-grade bucket with a valve at the bottom makes an excellent bottling bucket.
  2. Remove a pint of the beer and place it in a four-quart stainless steel sauce pan. Optionally, you could use a pint of water instead of beer.
  3. Add the recommended amount of corn sugar or dry malt extract to the sauce pan. Generally 3/4 cup of corn sugar or 1 1/4 cup of dried malt extract will do the trick. Most recipes specify the priming amounts.
  4. Bring the mixture to a boil while constantly and slowly mixing. Be careful not to allow the mixture to boil over.
  5. Continue the boil for at least five minutes and not more than 10 minutes. Remove the sauce pan from the heat. Place a cover on the sauce pan to keep out contaminates.
  6. Allow the priming solution to cool to room temperature. To quickly cool the solution, run cold tap water around the outside of the pan.
  7. Once cool, add the priming mixture into the bottling bucket. Be careful not to splash when adding the priming solution. You don’t want to add additional air that can lead to oxidation of the finished beer. To avoid aeration, slowly pour the priming mixture along the side of the bottle bucket then slowly stir the primed beer with a sanitized racking cane or long spoon.If dried malt extract is being used, you will notice the sauce pan has semi-soldified material at the bottom. Be careful not to pour this gunk, called break material, into the bottling bucket. Break materials can impart off flavors to the finished beer.
  8. The primed beer is now ready to be placed into bottles or a keg. Once the beer is primed, store it at room temperature for two to three weeks.

Kraeusening means to add fermenting wort (kraeusen) to a beer to cause a secondary fermentation. A commercial brewery may use the kraeusening process prior to cold storing (lagering) beer in a secondary. To the homebrewer kraeusening is an advanced form of batch priming. Kraeusening is useful for priming beer that has been lagering for an extensive period of time.

After several months in storage, the yeast may not be active enough to consume the priming sugars. To counter that situation, add a small amount of yeast in 1 1/4 to 1 1/2 quarts of the original unfermented wort. When used as a priming malt, the wort is referred to as gyle. When the gyle and pitched yeast combination reaches full fermentation (kraeusen stage), it is added to the beer as a primer.

While kraeusening may seem intriguing, it is certainly not for the faint of heart. It is often difficult to achieve the desired specific volume of carbonation. Extensive trial-and-error experimentation may be necessary to determine the amount of gyle needed for proper carbonation.

On occasion you may find that an entire batch of beer did not carbonate properly. Assuming you did not forget to prime the beer, flat beer is likely the result of carbonation leaking from poorly capped bottles. Other probable causes of flat beer are:
• Not enough priming sugar
• Inactive yeast
• Not allowing enough time for the yeast to consume all of the sugar
• Storing the primed beer at a temperature too low for the yeast to work.

The solution to under-carbonation is to add additional priming sugar and a small amount of rehydrated dry yeast to each bottle.

The other possible carbonation problem is over-carbonation—the gusher. Over-carbonation is likely the result of over-priming. Too much fermentable sugar allows the yeast to produce too much carbonation. Over-carbonation can also result from not allowing the beer to completely ferment out. In that case the beer, once primed, contains far too many fermentables.

Bacterial or fungal infection can also cause over-carbonation. Micro-organisms release various gases in addition to the carbonation being created by the yeast. Infected beer is normally discarded.

Like flat beer, over-carbonated beer can often be salvaged. Begin by chilling the beer. The lower the temperature the better, but don’t freeze it. Cold beer is able to hold the carbon dioxide in solution, temporarily preventing the beer from foaming over. Next, loosen the caps to let the gas escape. Allow the beer to stand for 30 minutes and recap with new sanitized caps. Store the beer for several days. If the beer remains over-carbonated, repeat the process.

Natural conditioning produces carbonation in the old style of brewing. By contrast artificial carbonation is a much faster process, allowing you to enjoy your beer immediately. Many homebrewers, however, feel that the extra effort involved in natural conditioning, as well as a little sediment in the bottom of the bottle, seems a fair tradeoff for the results achieved.

Typical Priming Amounts for Naturally Conditioning Beer in Bottles

Low carbonation:

  • Approximately 2.2 volumes of CO2.
  • Use 1/2 cup of corn sugar or 7/8 cup of dried malt extract for priming five gallons of beer.
  • Suitable for barley wine, fruit ales, porters, special bitter, and stout.

Medium carbonation:

  • Approximately 2.2 to 2.5 volumes of CO2.
  • Use 3/4 Cup of corn sugar or 1 1/4 cup of dried malt extract for priming five gallons of beer.
  • Suitable for altbier, Belgian abbey, English pale ale, Oktoberfest, and pilsner.

High carbonation:

  • Approximately 2.5 to 4 volumes of CO2.
  • Use 7/8 cup of corn sugar or 1 1/2 cup of dried malt extract for priming five gallons.
  • Suitable for American light, Belgian lambic, weisse, and wheat beer.
Issue: August 1995