Is It Better To Krausen or Carbonate?

American Brewer  Nov. 1934

By E. H. VOGEL JR., Assistant Brewmaster, Griesedieck Bros. St. Louis, Mo.

The question, as to which of the two methods generally used in American brewing practice for impregnating beer with carbon dioxide is of greatest advantage, has become a favorite topic of discussion among brewers. For this reason a detailed presentation of all the basic facts is submitted herewith so that the advantages and disadvantages of both systems may be compared and a conclusion reached on the basis of both theoretical and practical considerations.

Stability Of Product.
Most brewing technologists agree that the carbonated product is the more stable of the two. In the krausening process a fully matured beer is subjected to the admixture of a certain percentage of wort which has just reached the krausen stage. The sugar thus introduced will not be fermented completely, leaving an excellent media for continued fermentation and causing the finished product to be less stable. Coupled with this disadvantage is that of protein instability, which likely is to result because the time period and low temperature needed for the precipitation of insoluble proteins contained in the krausen, generally are not available in this process.

The carbonating system presents a fully matured beer for Saturation with carbon dioxide, and eliminates the necessity of adding young beer for the purpose of generating the required gas. The carbonated product thereby remains fully matured and goes out to the public with a better chance of maintaining its clarity.

Hop Flavor.
A Smooth character and fine hop taste must be attributed to the complete settling out of the hard resins which usually give beer a harsh flavor. As previously stated the carbonated product remains fully matured and hard resins are n0t likely to be present. In the krausened product, however, a sweeter taste is apt to result from the unfermented sugar, while, on the other hand, a more harsh hop flavor remains due to lack of precipitation of some of the hard resins. The process to be used and the character to be developed in the finished product depend upon the personal preference of the majority of the beer drinkers in the locality where a beer is sold.

Krausened beer presents a more full-bodied product in comparison with the snappier carbonated beer. Climatic conditions likewise must be taken into consideration regarding this point for a satiating beer of the krausened type is not as good a thirst quencher, particularly in dry, hot sections. The greater “full-bodiness” of the krausened beer ls attributed to the extract added at the time of krausening.

The krausen process, as followed according to usual American practice, requires almost equal capacity in storage tanks—which need not hold pressure—and pressure tight krausening casks or tanks. A plant equipped for carbonating can get along with relatively few pressure tanks. These facts are of importance, for flexibility of any equipment is a valuable asset. A plant constructed solely for the krausening process may at times be handicapped if, for some reason, this process is not entirely successful in giving adequate life and foam stability to the beer, and the additional equipment necessary for emergency carbonating is missing. On the other hand, a carbonating brewery with limited pressure tank or cask capacity, will find its output curtailed, if the trade unexpectedly presents a decided demand for krausened beer.

In this respect the carbonating process attains its great popularity and presents probably the most important reason for its increased use. The original investment, as well as the savings on maintenance and refrigeration, rightfully deserve serious consideration. In the krausening method the impregnating of beer with carbon dioxide takes about three weeks, during which time the process consumes tank space and refrigeration, which the carbonating process largely eliminates—the gas being injected mechanically by means of a carbonator and the beer merely being pumped from one tank to another. It is a generally admitted fact that carbonated beer should be impregnated at least twice before being racked into packages, but even with this procedure the storage capacity required is materially less than in a krausening brewery of equal output. For this reason the carbonating set-up with its shorter process is financially a more attractive investment.

Flavor And Foam Holding Capacity.
Theoretically the foam holding capacity and flavor of a carbonated product are not as good as those of a krausened beer. There are several reasons for this, foremost of which seems to be that the naturally impregnated carbon dioxide carries with it esters generated during the fermentation. These are removed almost completely from gas compressed for use in the carbonating system. While it remains a well-known fact that the carbon dioxide is tested for purity before collecting for carbonating purposes, there is no apparatus which also checks the by-products of fermentation which we term esters. This is an important item as was evidenced during Prohibition before the days of the de-esterizers. Secondly, by watching the temperature and controlling the bunging pressure in the krausening process, the carbon dioxide content of the beer can be fixed within quite narrow limits, while in carbonating the gas content of a beer depends on the experience and judgment of the brewer whose accuracy cannot be perfect.* Bunging pressure, time and temperature, control the krausening pro- cess, but in carbonating the end point is judged by eyesight. The value of this article can be gauged only by the yard- stick of interest which it arouses. If it causes comment and reply, or constructive thought, then it has accomplished its aim.

* This article was received before the publication of John A. Harting’s description of a method and apparatus for accurately determining carbon dioxide content in beer.  See “Communications: Master Brewers Association of America. V3, No, 3,”  September, 1934.

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