SEGUNDA PARtE
2. El Plan Estratégico de Gobierno Electrónico
Malt syrups and dried malt extracts offer the great convenience of achieving the high original gravities needed for these styles without a long, complex process. This is because they can be diluted to just the right level. However, they have their own difficulties, and I am unaware of any commercial German brewer using these ingredients to produce Bock beers.
The problems with extracts are three: potential oxidation in handling and storage, low FAN content, and adulteration with sugar syrups. These problems can be avoided and excellent beer can be created with extracts, but doing so requires getting fresh product from a reliable source, and performing a mini-mash to help overcome problems that might arise from the latter two areas.
It is critical to the quality of the beer, and of dark beer specifically, that it be created with unoxidized wort.40 As has been made clear in the professional and homebrewing literature, the melanoidins which are so crucial to the flavor and stability of Bock beers will quickly cause the beer to become stale and unpalatable once oxidized.22 Oxidized melanoidins are at the beginning of several different oxidation reaction chains (mentioned above in the section on melanoidins) that can cause problems with haze and off- flavors. Any oxygen that might be included in the malt extract during the packaging process will have a long period before connecting with the melanoidins in the wort.
Oxidation also increases wort color. An increase of oxygen content from 0.2 mg/L to 1.0 mg/L can increase wort color by 0.38 °SRM (1 °EBC). A further increase to 10.0 mg/L can add another 1.4 °SRM (3.5 °EBC). This darkening does
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not come with the same aromas and flavors expected from good quality malts.
Darkening can be increased during extended storage times due to the Maillard reactions continuing unabated. In these conditions, a high concentration of reducing sugars and free amino acids are present. However, the different (lower) storage temperatures emphasize formation of a different balance of melanoidins than are created in the high temperature malting, mashing, and boiling processes.37 This is why it is important to get fresh extract.
Long storage times are sometimes encountered with the distribution and retailing of malt extracts. Ask your supplier when they received their shipment; encourage them to find out how long their distributor has had it. If you start with old extract, your beer could be old even before it has finished lagering.
Other concerns, that have been reported in many publications,42,43,44,45 indicate that nearly all of forty-four commercial lager extracts purchased from maltsters and from home brewing retailers in Canada had significantly lowered levels of free amino nitrogen (FAN). Many levels had lowered below the point where proper yeast metabolism could be maintained in a standard beer wort of 1.048 (12 °Plato). Some of these extracts had levels that were only half or a third of the generally recommended minimum of 150 mg/L. A Bock beer wort created exclusively from one of these extracts, in spite of the higher original gravity (and correspondingly higher FAN concentration), could still fall at or below the minimum FAN requirements. Further evidence42,45 shows that FAN utilization by yeast in an extract wort is significantly reduced, regardless of the initial FAN concentration. This evidence leads to the concern that
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the FAN present has undergone some change during processing that renders it less available to the yeast.
It is not clear why this comes about. One might speculate that as the extract ages and the Maillard reactions continue, a significant fraction of the FAN becomes bound up in melanoidins. If this were to prove true, fresh extract would again be the appropriate solution, but the experiment has not been conducted. Regardless, reduced FAN levels can be counteracted by adding fresh malt back into the beer wort by doing a mini-mash.
Another consideration in examining the use of extracts was reported in the Journal of the American Society
of Brewing Chemists.42 Disturbingly enough it was reported
that significant evidence of apparent adulteration of some extracts with glucose syrups had been found. (Unfortunately it is unclear who is at fault for the detected adulteration, thus concrete action has yet to be taken.) This not only has the effect of diluting what FAN is available but changes the sugar balance of the resulting wort. This change can have a profound effect on the yeast, because yeast uptake of sugars follows a fixed schedule. Since yeast metabolizes sugars in a rigid order, with single chain sugars used first, high quantities of them suppress the uptake of more complex sugars like maltose.
In a normal all-malt Bock wort, glucose makes up about 25 percent of the carbohydrates; maltose and maltotriose make up as much as 45 percent38 (dextrins and other minor sugars make up the rest). A wort created from an adulterated extract could easily have these percentages reversed. In such a situation, the Crabtree effect can inhibit the yeast from entering the respiration phase,22 thus preventing the high reproduction rates needed early in the fermentation to obtain the optimal yeast density in the beer.
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This can lead to long, disordered fermentations, which can provide opportunities for invading organisms to gain a beachhead in the wort. Indeed, Journal of the American
Society of Brewing Chemists42 notes that comparisons of
attenuation of the original 1.048 (12 °Plato) wort were cut off after reaching 1.024 (6 °Plato), rather than the planned 1.012 (3 °Plato), because some of the test worts created from extracts never reached their appropriate final gravities.
Dried malt extract (DME) is created by spraying hot wort through a partial vacuum (which lowers the boiling point of the water in the wort), evaporating the water and leaving the wort solids behind. One of the conveniences of DME is that it is easy to measure out and divide up.
However, once the package is opened, another factor comes into play. DME is very hygroscopic, meaning that it will pull moisture out of the air, and begin to liquefy. It is the liquefaction that allows oxidation reactions to proceed, so this must be prevented. DME, once opened, should be kept in a closed, cool, dry environment. A refrigerator or freezer is a good location, since the cold air can hold much less moisture.
There is no information regarding possible adulteration of DME42,45 as only extract syrups were tested.
Another point of consideration in choosing an extract product: one should be guided by the intended use described on the extract's label. Extracts made from lager malts should provide more of the sulfury, lager character that will help to distinguish the flavor and aroma characteristics of these beers. Extracts made from continental malts have a better chance of containing the crucial melanoidin balance that is wanted.
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that the evidence shows they can be quite variable from brand to brand.42
One should attempt to get the freshest product, from a well known and respected source. Store it in a cool place once purchased, and use it up quickly. Once an extract is discovered that produces a quick and complete fermentation, patronize the producer. Extracts are not interchangeable parts of a beer, and a bargain price does not always purchase a quality product.
The bottom line on extracts is that they can make the process far shorter and more convenient, but insufficient information is available to guide the brewer in making the correct product choice. By formulating recipes with significant amounts of added malts in a mini-mash, potential problems can usually be minimized. This is particularly important for Bock beers, that depend so heavily on the quality of the malt aroma and flavor.
HOPS
Because bitterness can be discussed easily in terms of quantifiable levels, this tends to overshadow other considerations when choosing boiling hop varieties. Realize that even though such hops are usually discussed only in terms of the bitterness they bring to the beer, they will also contribute differing flavors. Bitterness is only one dimension of hop character, even in hops boiled an hour or more.
Hopping rates are affected by the kind of brewing liquor in use. If the brewing liquor is highly carbonate, as is the case with traditional Dunkles and Doppelbocks, smaller quantities of noble hops should be used in order to maintain the elegance of the beer. Carbonates enhance the perception
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of bitterness from the hops.36 Carbonate waters have been called “hop savers”,29 but in fact, they emphasize the strong bitterness of the hops and tend to hide the finer flavors. High α-acid hops are particularly affected by this, and yield very rough, coarse flavors that quickly become unpleasant.
Physical characteristics can be important as well. Even though the higher gravity wort of a Bock beer will tend to reduce the amount of bitterness available from the hops,46 the decreased bittering rates keep the total mass of hops used low. Because hops help to coagulate proteins and therefore clarify the beer, the tiny quantities of high α-acid hops that might be called for on the basis of bitterness alone could prove insufficient for clarification purposes. This is especially so in a high protein wort such as a Bock. This could be further emphasized by other processing choices like a shorter boiling time and an infusion, rather than decoction mash.
The most local product for Bavaria comes from the Hallertauer region south and east of Nürnberg. Hersbrucker or Hallertauer Mittelfrüh are the most highly prized products of the Hallertauer region.
In Helles Bocks, where carbonate levels will be low, higher hopping rates should be used, but the fine noble flavors of Hersbrucker, Hallertauer Mittelfrüh, Spalter, and even Tettnanger are still preferred. These give the cleanest, most elegant, and balanced flavors to the beer.
American varieties of the Hallertauer Strain, like Mount Hood and Liberty, also work well in Bock beers because they have similar flavor and aroma characteristics to their German forebears.
Other, more distinctive, varieties can be used in blends to tame them a bit. Saaz, Styrian Goldings, and some English and English-derived strains like Kent Goldings,
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Fuggles and Willamette can be used in blends with the more traditional hops mentioned above to give unique flavor and aroma notes. Although these would produce less traditional beers, they would not be so strange as to break the Bock beer mold.
The strongly floral and very distinctive citrus flavor of Cascades can fight with the malt and lager characters of Bock beers. Although the author doesn't find this an appealing combination, especially in Helles Bocks, with North American brewers looking for very distinctive products, this elicits partisans on both sides.
YEAST
The yeast pitched must be a good strain in excellent condition, for the rigors of a high-gravity wort fermentation can otherwise prevent the completion of the task. There must be a large quantity of yeast, and it must already be acclimated. Only when the yeast is at its peak, can it produce a clean product that is free of off-flavors.
The high original gravity, combined with the high final ethanol content work together to inhibit yeast activity. The high concentration of sugars creates osmotic pressure on the yeast cell which, without effort on the part of the cell, would draw water out of the cell's cytoplasm. This effort distracts the cell from other metabolic endeavors, like reproduction, respiration, and fermentation.
Ethanol, as a waste product, is toxic to yeast. This effect is heightened as the fermentation progresses and ethanol concentration goes up. In some cases,47 this can cause the complete cessation of fermentation well short of the attenuation limit of the wort. Worts with starting gravities above 1.096 (24 °Plato) never reach the attenuation
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limit with lager yeast.
The strain of yeast chosen should be a known performer, capable of working in a high-gravity environment and still completing the fermentation. It should produce as neutral a flavor as possible, since fermentative byproducts are generally perceived as flaws in the Bock styles.
It must not be of a highly flocculative nature; such yeast strains do not stay in suspension long enough to complete the fermentation, and so the resulting beer will be sickly sweet. In such a situation, the yeast may also leave a strong, unwanted diacetyl component. This comes
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about because the yeast falls out of solution before all the sugars are used up, forcing it to metabolize the diacetyl produced early in the fermentation.
Yeast propagation is discussed further in the recipe chapter, but it must be kept in mind that yeast grown on a medium without maltose will require an adaptation period of as much as a day, slowing the start of the fermentation.47 Although optimum yeast reproduction can be obtained with continually replenished and aerated weak (0.5 percent) sugar solutions, such yeasts are not adapted to brewery conditions. Typically, yeast propagation in the brewery is accomplished with all-malt wort.
The author has had good results with both commercially available strains and those collected from continental and large breweries in the United States. Any o strain with good alcohol tolerance that meets the other requirements set forth already will produce a fine Bock. Wyeast Bavarian (2206) is a good place to start. Mixed reports have been aired on Wyeast Munich (2308). Apparently it is somewhat unstable and can produce high levels of diacetyl, therefore requiring special handling (a diacetyl rest) at the end of the primary. Wyeast Bohemian (2124) tends to produce more esters than are called for in the style.
If the brewer is interested in attempting the reproduction of beers from previous centuries, there is room for greater creativity. Before the middle 1800s, single cell cultures were unknown, and mixed cultures of ale yeast were the rule. Lagering has always been practiced to some extent, though, with regard to these styles, so an ale strain that is cold-tolerant is important. Alt beer strains, such as Wyeast German Ale (1336) come to mind, but the ever popular Sierra Nevada/Narragansett yeast (Wyeast American 1056) seems to
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be tolerant of temperatures down to 50 degrees F (10 degrees C). Both of these strains are good fermenters and do not produce high levels of esters or diacetyl.
The further back in history one goes, the more likely it becomes that some level of lactic acid producers would have been included in the microflora. One should turn to the practices of the rural Belgian brewers for a view back in time. (Suggested reading is Lambic by Jean Xavier Guinard.)24