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A branch point within a molecule of amylopectin. Three glucose residues linked 1 –> 4 with the top one branching off with a 1 — > 6 linkage.
It’s Starch Week on Beer and Wine Journal, and today’s topic is amylopectin. Amylopectin is one of the two components of starch, the other being amylose, which was covered on Tuesday.
Today is the first day of starch week on Beer and Wine Journal. (It’s like Shark Week on Animal Planet, but instead of ridiculous made-up crap about sharks, it’s facts about starch.) See the introduction to the series for an overview of the topics to be covered. Today’s post deals with amylose, one of the two main components of starch.
Glucose molecules joined in alpha 1 –> 4 linkages. In barley, amylose molecules typically range from 500 to 5,000 glucose residues.
The articles that compose this series on starch will have a few common themes. The most important is that the word starch refers to a variety of things, not a single, defined entity. For example, starch is composed of amylose and amylopectin. Any combination of these two molecules — from 1% amylose to 99% amylose — would be considered a starch, even though differing mixtures would have different properties.
Additionally, in real life situations, starches maybe complexed with proteins and other molecules. These other molecules can change the properties of the starch. Starch is also packed into different sized granules, which affects its solubility. Even heating and cooling starch can change its structure and its properties.
Much of the (fairly) recent scientific work on barley starch should be of interest to advanced homebrewers or homebrewers with an interest in biology. This post is an introduction to a series of articles that will review what modern science has revealed about barley starch. Recently, I posted a series of articles on enzymes for brewers. Although it dealt with all brewing-relevant enzymes, not just starch-degrading enzymes, you can look at these starch articles as covering a lot of the same or similar ground, but from the perspective of the substrate, not the enzymes. (There will also be a few new enzyme-related topics, as well)
In this article, I will give an overview of the subject. In the subsequent articles, I will fill in all the details. In the individual articles, I will try to explain the topics so that you don’t need an extensive background in biology or chemistry to understand them.
This is the final installment of the series on the efficacy Clarity Ferm, the enzyme that purports to produce gluten-free beer, from Dr. Chris Hamilton of Hillsdale College. The series began on Wednesday. Yesterday’s installment described the two sets of experiments. In the first, differing amounts of Clarity Ferm were used to treat different aliquots of cream ale. In the second, different mash schedules were used to produce a stout. Clarity Ferm was added to half of the stouts. The idea was to test if a step mash — that contained a “protein rest” — would lower gluten levels by itself or in conjunction with Clarity Ferm. Here are the results. Hear an interview and tasting of samples on Basic Brewing Radio – September 4, 2014.
This is the second part of a 3-part article, by Chris Hamilton of Hillsdale College, examining experimentally if Clarity Ferm reduces gluten in homebrewed beer. The introduction was posted yesterday and the results will be posted tomorrow. Hear an interview and tasting of samples on Basic Brewing Radio – September 4, 2014.
TheRIDASCREEN® Gliadin competitive kit from R-Biopharm.
The overall goal of these experiments is to determine if Clarity Ferm does indeed reduce the level of gluten and related proteins and peptides to acceptable levels. The first set of experiments was done to determine the amount of Clarity Ferm needed to reduce the gluten to acceptable levels. The second set of experiments was done with a different beer and all trials done in triplicate as the additional variable of differing mash conditions was used to determine if a protein rest would aid in gluten reduction.
What happens if you pitch one package of liquid yeast (~100 billion cells) to ale worts of various volumes and “gravity points?” Gravity points are the last two digits in the three digits following the decimal point in specific gravity. For example, a wort of SG 1.048 is said to have 48 gravity points.
Brewing the best beer possible requires the brewer to pay attention to each step during wort production and fermentation, and to execute each well. There are no “silver bullets” when it comes to making beer. In other words, there are no “do this one thing and your beer will turn out great every time” tricks to brewing — you need to do everything well to brew the best beer.
There are, however, practices that consistently lead to better homebrew, when all other things are held constant. I would argue the most important of these is raising enough yeast for an adequate pitch. For most homebrewers, this means making a yeast starter. As with most techniques in homebrewing, there are acceptable ways to make a yeast starter and the best ways.
A variety of potato cultivars. (USDA photo in the public domain.)
Potatoes are a common, inexpensive vegetable. And those starchy tubers can be put to use in brewing. Potatoes can be used in any recipe that calls for a relatively flavorless starchy adjunct, such as flaked barley, flaked maize, or flaked rice, or when sugar additions to the kettle are called for. They are easy to use in the brewhouse, and are a fun experience for home gardeners or adventurous brewers to try.
Use your favorite liquid yeast strain for flavor and aroma, then use a neutral yeast strain to shore up your pitching rate.
Pitching rate, the number of yeast cells used to inoculate a given volume of wort, influences several things in the brewing process. Higher pitching rates lead to faster fermentations — they start faster and finish faster. Higher pitching rates also lead to finishing gravities closer to what is predicted by a forced fermentation test. In other words, the yeast utilize all the carbohydrates that they can. In contrast, in severely underpitched beers, the yeast may quit early and leave fermentable carbohydrates behind, resulting in a higher final gravity (FG). Low pitching rates are frequently the cause of stalled or stuck fermentations.
For “characterful” yeast strains that produce plenty of fermentation byproducts, higher pitching rates are associated with “cleaner” beers. Some Belgian ale strains produce an estery, “spicy” aroma when slightly underpitched, but produce a cleaner beer when pitched at a higher rate (to a well-aerated wort). Temperature also plays a major role, with higher temperatures leading to more fermentation byproducts.
This is true of White Labs WLP530 (Abbey Ale) and Wyeast 3787 (Trappist High Gravity) yeast — larger than optimal pitches, thorough aeration, and low temperatures (within the usual ale fermentation range) lead to clean fermentations. It is also true that the “banana ester” level in German hefe-weizens can be manipulated this way.
Homebrewers who are concerned about their pitching rate generally consult a pitching rate calculator, then make a yeast starter of the suggested volume. However, if your brewday arrives and you haven’t made a starter, there is a way to “cheat” that may come in handy occasionally.
He’s not dead yet, but he’s looking a bit peaked.
In 1941, the US entered World War II. The following year, in the United States, 17 million acres were planted to barley. At the time, barley was grown as animal feed and for malting. (Malting is the process of turning barley seed into malted barley. Malted barley is the major ingredient in beer and some distilled beverages.) As today, a tiny amount went to human consumption and industrial uses. And of course, some amount of barley grown every year supplies farmers with seed for the next year. As it turns out, after years of increases in barley acreage since the mid 1800s, 1942 was the peak of barley production in the US.
After 1942, production bounced around before landing at around 8 million acres planted in 1987. From there, the numbers began to slide consistently, with barley acreage losing over 300,000 acres per year. (Numbers from the Nation Barley Growers Association.) Last year, only 2 million acres of barley were planted in the US. In addition, barley stocks — stored grain held in reserve — were at or near historic lows.
Acreage in Montana and Idaho, two major barley growing states, has seen only modest declines in the past two decades. In contrast, Minnesota and North Dakota have seen production fall sharply. The number of bushels produced Minnesota fell by roughly half from 1991 to 2000, then stabilized. From 1991 to 2011, barley production in North Dakota — until recently the top barley-growing state — fell from more than 135 million bushels per year to less than 20 million.
Brewery-grade malt extract is made from wort that has been boiled. All that you need to do to turn it into wort is dissolve it and sanitize it. (Canned extract should already be sanitary.)
In the early days of modern homebrewing, many 5-gallon (19-L) homebrew recipes called for boiling several pounds (a few kilograms) of malt extract in as little as 1.5 gallons (5.7 L) of water for 60 minutes. This thick wort would then be diluted to 5.0 gallons (19 L) in a bucket or carboy fermenter. If you followed these instructions, you ended up with beer (and you were psyched) — but you noticed that the color was frequently much darker than a comparable commercial beer.
As the sophistication of homebrewing knowledge increased, brewers were told to address the problem by boiling larger volumes of wort. (Buying fresh extract also helped.) This helped to a degree, but homebrewers wishing to make very pale beers were often left disappointed.
In the early 2000s, homebrewers started withholding a portion of their malt extract until the end of the boil. The idea behind this was that brewery-grade malt extract was made from wort had already been boiled. It did not require the long boil that all-grain wort does to coagulate the break material. All that is required is some time exposed to heat to sanitize it. In addition, by boiling your hops in low-gravity wort — made from steeping grains and small amount of malt extract — your hop utilization would improve when compared to boiling them in a very high gravity wort. This way of brewing — sometimes called the late extract addition method — quickly became standard practice.
Although everyone does this now, new brewers may wonder why and intermediate brewers may wonder about some of the variables in the process. With that in mind, here is a rundown of adding malt extract late in the boil and how it influences the character of your beer.
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