Froth! 

The Science of Beer

Mark Denny

2009, HB, 183pp
The Johns Hopkins University Press

£13.50 delivered from Amazon

Reviewed July 2012

Mark Denny is a homebrewer and a physicist. In the Introduction he sets out his stall: “My book is unique to the best of my knowledge, in that it unites brewing with accessible physics.” I imagine that at this point many of you will move along but I rather like the idea. After all pretty much everything is physics, even beer. But if mixing physics with beer isn't for you then it gets worse—there's mathematics too. (I'm not selling this well, am I?). But panic not, the maths can be bypassed—that's what I did most of the time.

Before getting to the science Denny outlines the history of beer and brewing. Maybe he should have stuck to the science. This chapter is riddled with inaccuracies and not-quite-accurate assertions. Did Balling introduce the hydrometer into brewing in 1843? That must have surprised Baverstock you was using one in 1770. Is porter really stronger than stout? Is stout usually dry? Guinness has been so only since the 1950s and London stouts never really were. This chapter is too long and a rather out of place. This is a book about “the science of beer”—get to the science! And I hated the stupid interlude inserted to break the chapter into two.

Next up is How to Make Good Beer at Home. Still no science then. This is a very basic introduction to homebrewing but at the same time idiosyncratic and opinionated. Certainly not for the homebrewing purists. Denny advocates natural cooling of wort, plastic bottles etc. Personally I don't have too much of a problem with that but like the previous chapter this seem a bit out of place in a book about the science of beer. Who is the book aimed at? The general reader? The beginner? Or the more advanced brewer? I would have thought it was the latter in which case a homebrewing primer is an unnecessary waste of space.

There are some odd mistakes for a scientist to make like stating that crystal malt is an adjunct: the clue is in the name, surely—it's a malt. And using the yeast from bottle conditioned beer: ”Don't throw away the gunk—feed it with yeast nutrient...and pitch it into your next brew. It will go like a rocket.” Probably not.

Finally, nearly halfway through the book we get to the science. The book gets much better from here.

Yeast Population Dynamics

Quite a lots of mathematical formulae from here on but these are explained and can be skimmed over and the text will still make sense.

This chapter contains one of the best description I have read of why yeast pitching rate is important. Clear, concise, and well explained both mathematically (by formulae) and in the text. The maths can be hard and is mostly beyond me but the explanations are good.

Brewing Thermodynamics

Sounds a laugh-a-minute, doesn't it?. But, of course, temperature control is a fundamentally important part of brewing so this is relevant stuff. The chapter covers a whole range of situations such as the heat produced by yeast during respiration, heating the mash, cooling the wort, temperature control etc. Lots of good stuff.

Now it has to be said that the design of the formulae and the associated explanations is a bit poor. New terms are introduced and the explanation of what they represent can be hard to find, sometimes hidden in the text of the next paragraph. Poor book design, in fact.

One thought provoking fact: enough heat is produced by the fermenting yeast in a standard wort to boil the whole batch. Lucky that heat is lost from the fermenter then.

Bubbles

Bubbles are everywhere in brewing. You might have noticed that. I found this chapter really stimulating. They is quite a lot of abstruse science, and I am sure some of it isn't that important, but most of it was absolutely fascinating. Fermentation is discussed in some detail and we learn that a typical homebrew fermentation might generate 35 billion bubbles. See what I mean? Not terribly useful but interesting and dead good for boring the guys down the pub. Denny points out that (for the US, I think) 0.5% of all carbon dioxide emissions are produced by beer production.

Beer froth and head production turn out to be more complex that you might think. Hey, one paper on the subject received an Ig Nobel Prize. The head on a beer is a surprisingly complex and dynamic system as Denny explains. He also discusses the background to the use of nitrogen/mixed gas and also shows why it isn't terribly beneficial to beer flavour. He gives a great explanation of how a widget works. They are surprisingly simple and are, in effect, a type of sparkler. Mention is made of disproportionation, which is another good one for use down the pub, and negative bubbles (a spherical layer of gas with liquid inside and outside of the sphere.

This chapter is probably the most successful of the book and is full of fascinating insight and some interesting science.

Fluid Flow

The final “science” chapter uses its title rather liberally. Most of it is taken up with the mathematics of bulk beer distribution which is, just about, an example of fluid flow. This is the only section where I found my inability to understand the mathematics frustrating. It would have been helpful to have had the various formulae more fully explained and not to have taken so much on faith. Maybe an appendix for thickos like me could have been added?

A brief discussion of how beer is moved from cellar to bar and an appreciation of how complex the action of drinking a beer is in terms of physiology, completes the chapter.

There are a few odd assertions—are electric pumps replacing beer engines on the bars of English pubs? I'm not sure when I last saw an electric pump. I used to love watching a diaphragm pump dispensing a pint of Bank's mild when I were a lad. But then earlier in the book there was the assertion that the barrel (36 gallon) and the pin (4½ gallon) are the most common UK cask container size when the firkin (9) and the kilderkin (18) are, by far, the most common size encountered.

Final Thoughts

Not a lot to say about this chapter. Simply a summing up of what went before.

Throughout the book some of the graphs are poorly designed and sometimes inappropriate for the data they depict—line graphs where bar graphs would have been better, for example, which is rather odd for a book published by an university press.

The very simple brewing technique described is at odds with some of the science explained, especially in the thermodynamics section.

The book is a good quality hardcover, nicely printed, with a sown binding. In fact the cover is so substantial, for the size of book, that it may constitute a dangerous item. Don't try and take it onto an airplane.

Froth! is a brave attempt at a different homebrewing book. It contains some thought provoking information and certainly encourages the reader to look at things from a different perspective. But it is not a great book. Nearly half the book is not, in fact about “the science of beer”. Most of the beery science is interesting, some of it thought provoking, and some of it might even improve your brewing. Although the text is designed so that the mathematics can be missed out it is a pity that some space could not have been found to more fully explain how the formulae are derived. The mathematics is the backbone of several sections and not being able to understand it is very frustrating.

Froth! is not a book for everyone and newby brewers should avoid it if they don't want their head to explode. The more advanced and/or technical brewer will certainly get something from the book and it encourages the assessment of the brewing process from a new perspective.

So recommended (but with significant reservations) especially at £13.50 for a “proper” hardback.

Brewing

Michael J Lewis & Tom W Young

1995, PB, 260pp
Chapman & Hall

£43.34 delivered from Amazon

Reviewed May 2011

 

This is a review of the first edition of this book. The second edition (larger at 408pp) is currently available but I don't have that in my library. Yet.

I am what you might call a technical home brewer. I don't brew in pots and pans in the kitchen but have a permanent brewery and temperature controlled fermenters permanently set up in the garage, for instance. And I love the science stuff. I am also from the UK and most of the beers I brew are British in style. Trust me this is relevant to the review.

There are a lot of home brewing books out there including any number of basic how-to-brew titles and a smaller number of more advanced guides. These vary in quality from the outstanding to total rubbish. There are also a surprising number of professional brewing text books. Most of these are of limited use to home brewers or microbrewers because they deal with modern industrial brewing using techniques and methods out of our price or technological range. A smaller number do have useful information, at least in part. The greater proportion of English language brewer's books of both persuasions are US in origin and brew with a US attitude.

“Brewing” doesn't fit into any of these groups. Michael Lewis is based in California and Tom Young in Birmingham, UK. Lewis gained his PhD Birmingham University in the UK, however. The book seems to be aimed at small scale commercial brewers and has a distinctly British attitude to brewing, and this is reinforced by the use of litres, celsius and kilograms alone in the body of the text. This is a pretty unusual combination and makes it a valuable book in itself, especially to us Brits.

Now lets be clear: this in not a let's-start-brewing book. It assumes a level of technical and, especially scientific, knowledge. If you didn't study science to advanced school or, better, college level you are going to struggle. That's not a criticism of the book, just a reflection of who it is aimed at. As a random example you need to comfortable with stuff like this: “Carboxypeptidases survive kilning but endo-ß-glucanases are much more heat labile. There is a danger therefore that if ß-glucanolysis is incomplete in malting, ß-glucans could dissolve in mashing under the influence of a carboxypeptidase (called solubilase) with insufficient endo-ß-glucanase to reduce its viscosity.” See what I mean?

To be fair, the authors say in the preface, “it is our intention and our hope that this book will provide a useful and practical grounding in the fundamentals of brewing science and the practice of brewing.” It is significant that they put science before practice because that is the way the book is arranged.

The book is logically organised and follows the brewing process from beginning to end. After a simple Overview of the Brewing Process in proceeds to Basic Chemistry for Brewing Science. In many ways this is the most important chapter in the book and its 28 pages need careful reading. Although the chapter starts with the basics of water chemistry within the first paragraph it is clear that the authors concept of basic assumes the reader understands terms such as “element”, “valence”, and “Lewis structure”. If you don't it would be best to put the book down and get hold of a science primer because without some underpinning knowledge this chapter and most of the rest of the book is going to be meaningless.

If you pass the Basic Chemistry Test the rest of the book lies before you. All the usual stages are covered from a scientific point of view although at the same time the focus is on small-scale, low technology brewing. For instance the chapter on Mashing Technology devotes most of its description of the mashing process to simple infusion mashing although temperature-controlled mashing, decoction mashing, double mashing, lauters and mash filters are covered. The authors make the point that “infusion mashing is particularly attractive in small breweries because the vessels are simple and cheap, and easily scaled to their low output.”

The rest of the process is examined in similar vein. There are a large number of line drawings, graphs, tables, and chemical pathways illustrated throughout the book including such delights as the Embden-Meyerhof-Parnas pathway, the Burton union sytem of traditional fermenters, the design of a “python”, and the function of a beer engine. Sadly the authors couldn't resist the temptation to include that really dodgy tongue map of flavour sensing areas. Mind you the accompanying text is a lot better.

I particularly like the chapters of yeast and fermentation. This, of course, covers the biochemistry of the process in some detail, as you would expect. Yeast culturing and propagation is considered. The delights of long term yeast storage are discussed (clearly beyond most home brewers or microbrewers) but this is balanced out with much more practical discussions of cropping yeast for re-use and the use of dried yeast (even though there will be those rolling there eyes at the very thought). Although not a laboratory manual simple laboratory methods of practical application are discussed such as storage yeast on agar and yeast viability counts using a light microscope and haematocytometer.

“Brewing” balances on a wire between a scientific treatise on the brewing process and a practical how-to-do-it manual. It pulls this off very well. If is a, relatively small, guide to the brewing process which contains most of the information a home- or microbrewer will ever need. It certainly deserves a place on the bookshelf of any brewer who has the scientific background to digest it. Recommended.

Who should buy “Brewing”?

Starting out home brewer: step away from the book.

Advanced home brewer: yes, if you have the science.

Microbrewer: why haven't you got it already?

Radical Brewing
Recipes,Tales & World-altering Meditations in a Glass
Randy Mosher
Brewers Publications, 2004
PB, 324pp
£9.88 delivered from Amazon

Reviewed January 2010


Randy Mosher is clearly a clever bugger. He not only wrote this book but designed it as well. More of which later.

Radical has a couple of distinct meanings which can be applied to the title of this book. First, going to the root or basics and secondly, far-out, wild or unusual, This is apt because the book does contain both elements.

This is not a book for the neophyte brewer but for someone who has a few brews under the belt and wants to find out more or expand their horizons and it will certainly do this well. Although all the information is there it is not organised in a way that would be easy for the starting brewer but of course there are plenty of other books or web sites which will fulfill this need.

The first half of the book deals with the brewing process and theory behind it: radical in the first sense. A lot of the information is seen from an historical perspective which I like because it accords with my outlook on brewing. Although this is quite detailed and in-depth Mosher's style is light and breezy and he gets his point across easily. He also, clearly, knows his beer history and has read and researched much more deeply the authors of some other, supposedly authoritative books (and yes, I am thinking of the Classic Beer Styles Series). For instance his brief description of the history of porter which, let's be honest, is a pretty contentious area is well balanced and thought out and avoids all the usual dodgy information. Mosher's views on brewing are always well reasoned and I rarely took issue with his suggestions. For instance in the hops section Mosher suggests there is no homebrew justification for high alpha hops and that pellets give an inferior flavour to whole flowers. That seems pretty much bang on to me. You might argue that the flavor of pellets is not "inferior" but it is well established that it is different.

There are some sections that work really well. I particularly liked the section on off flavours and how to mimic them. Not, I hasten to add, so that you may add them to your beer but so you can detect them and eradicate them! I also appreciated his approval of the use of sugars. Now I know to some brewers this is spawn-of-the-Devil stuff but, having overcome my CAMRA inspired aversion to sugar, I have come to appreciate it is often a useful, and sometimes a necessary, ingredient in beer. Annoyingly our US brethren seem to have, as always, relatively easy access to a greater range of this product than we do. Damn their eyes.

In the second half of the book there is more concentration on beers from around the world mainly, again, from an historical perspective. This is very wide ranging and there are some interesting beers to try or at least think about and perhaps inspire you. But there is also a element of that annoying (to me anyway) American habit of just chucking anything in willy-nilly and assuming it will be marvelous. Well it might be, but usually getting the quantities of flavouring additives (spices etc) right is pretty difficult and without considerable thought, and usually a bit of trial and error, the results are less than stellar. It is the US "can do" thing, I think. And why do you need to put mint in stout? It's not exactly lacking in flavour is it? And if you think of the difference between a Guinness clone and an imperial stout there is one hell of a lot of variety as well.

There are some odd errors, especially since it is obvious that Mosher is very well read in the brewing literature and well traveled. For instance a british beer barrel doesn't hold 31.5 gallons (although oddly the volumes of the kilderkin and firkin are correct) and Dorset isn't a short hop south of London. I was born in one and lived in the other. Dorset is definitely to the west of London. OK I might give you southwest.

I do have, however, severe issues with the design of the book, which was undertaken by Mosher himself. I don't know, but would hazard a guess, that he is a designer rather than typographer. The design looks modern and attractive at first look but it is a right royal pain to use. For instance on the facing pages 98 and 99 there is one illustration, two recipes in full page width tables and two small tables inserted into the text blocks. In all there are only eleven lines of type on the two pages. This sort of design is repeated throughout the book. So what's the problem? Well reading the text is repeatedly and frequently interrupted by the extra matter on the pages. The text is not allowed to flow, which is a pity because it is actually very good. You either have to stop reading to consult the tables, recipes, sidebars etc or ignore the extraneous matter on concentrate on reading the text through before returning to the other matter. This is what I did, which is not ideal, but I found the whole experience of using the book incredibly frustrating if I didn't. A pity: there is a much better book in there trying to get out.

So not a perfect book then. But certainly a useful, stimulating, and informative one. I am glad I added this book to my library. If you are looking to expand you knowledge of the history of beer and brewing or want to expand your brewing horizons to include a wider palate of beer styles, types, and flavours you could do much worse than Radical Brewing. Recommended.