Enzymes for Brewers (VI: Enzyme Activity in the Mash)

May 10, 2014 by Leave a Comment

This is the final installment of the Enzymes for Brewers series. 

2xfr_b_amylase

A ribbon model of beta amylase from barley.

Barley seed can sprout at temperatures as low as 34 °F (1.1 °C). The seedlings can survive overwinter at temperatures below freezing, although the plant does not grow at these temperatures. So, the enzymes in barley are active as low as 34 °F (1.1 °C). The amylase enzymes we use in brewing slowly turn the starch in this seed into sugar, which is used as fuel for germination and early growth. Eventually, the first leaf unfurls, and photosynthesis begins supplying the plant with sugar as the starch stores in the seed are depleted.

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Enzymes for Brewers (IV: Kinetics I — Substrate Concentration)

May 8, 2014 by 2 Comments

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This is the fourth installment in the Enzymes for Brewers series. 

 

Biochemists envision enzyme-catalyzed reactions as occurring in two steps. First there’s the formation of the enzyme-substrate complex. Then there is the subsequent formation of the product.

In most realistic situations — and certainly in brewing — the concentration of the enzyme is small compared to that of the substrate. As the concentration of substrate rises, so does the reaction rate, as the average distance between enzyme and substrate is reduced. Put more simply, in a brewing-relevant example, the more starch there is in the mash, the more likely an amylase enzyme floating in the liquid is to bump into a strand of it. At some point, however, enzyme activity does not increase as all the enzyme is tied up in enzyme-substrate complexes.

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Enzymes for Brewers (III: Review and Control)

May 7, 2014 by Leave a Comment

2xfr_b_amylaseThis is the third installment in my Enzymes for Brewers series. This article contains information for those interested in background material on enzymes, but none of it is specifically relevant to brewing. I will (finally) get into some general issues relevant to enzymes in brewing in my next two articles on enzyme kinetics. (These are already written, and I’ll post them Thursday and Friday.) In my final article in this series, I will review the relevant enzymes in brewing, what is known about them, and what this means to us as brewers. But first, given the complexity of the topic, let’s quickly review what was covered in previous articles.

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Enzymes for Brewers (II: Function)

April 23, 2014 by Leave a Comment

This is the second article in a series called Enzymes for Brewers. The first article covered catalysts and protein structure. This article — on enzyme function — is mostly background material, needed to understand the more brewing-relevant information to come. 

 

2xfr_b_amylase

Beta amylase from barley.

In this post, I’ll explain the basics of how proteins work. But first, since much of this may be new to some readers, let’s quickly review the information in the first installment of this series.

A catalyst is a molecule that speeds the rate of a chemical reaction, but is not used up in that reaction. Enzymes are catalysts that are biological molecules. Most enzymes are proteins, but a few RNA enzymes exist. Proteins are long strands of amino acids, joined end to end by peptide bonds. These molecules are “built” on a cellular organelle called a ribosome. [Read more…]

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Enzymes for Brewers: I

April 11, 2014 by 3 Comments
2xfr_b_amylase

Beta amylase from barley. The sections in gold are alpha helices. The sections in blue are beta sheets. The grey stretches are sequences of amino acids that lack secondary structure. (Diagram from Wikipedia, under Creative Commons license.)

Whether we know it or not, all brewers rely on enzymes in the brewhouse. This is a primer on the biology of enzymes, meant to give the interested brewer a more sophisticated understanding of enzymes. Nothing in this article will suggest radical alterations to your brewing procedures. However, a better understanding of enzymes may help you when things go wrong in the brewhouse — for example, if you mash at too high or too low a temperature.

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