Archive for March 2012

Day 199

March 30, 2012

Chronologically speaking, one-third of the way to the finish line; scholastically, almost half way there.

In Sensory Evaluation today, Mark Benzaquen subjected us to two “triangle tests”. We were given three samples of beer. Two samples were identical, one had been spiked with an off-flavour in about the concentration you would expect to find in a real beer. Our job was to identify the odd sample, and then try to identify the off flavour.

I successfully identified both odd samples, but only identified “metallic” as the off-flavour in the second sample. (DMS in the first sample eluded me.)

Then Mark tried a threshold test, spiking four samples of beer with increasing amounts of a sour vinegar flavour–50 parts per million, then 100 parts per million, 200 ppm and 400 ppm. Our job was to identify in which sample we detected something not quite right, and then the sample in which we could positively identify the off flavour. This would define our detection threshold and identification threshold for that flavour.

Turns out that with acetic sourness, I can detect something wrong at 100 ppm, and can identify the fault at 200 ppm. (That’s probably about average.) Yes, I also tasted the beer with the very high concentration of 400 ppm. Gnurk! Imagine adding vinegar to your beer. It wasn’t a pleasant experience.

Our tasting finished for the day, Mark then gave a lecture on some of the microbiological contaminants that can be found in the brewery, and the off flavours they can produce.

On to Microbiology, and an examination of the various ways raw ingredients can bring microorganisms to the table–barley can be infected with fusarium head blight, for instance, which will cause the barley to produce oxalic acid, which in turn will cause both haze and gushing. Water can be a huge source of microorganisms–they can even hide away in an activated carbon filter–and yeast can be contaminated with bacteria and wild yeast.

On to a closer look at the principle organisms responsible for a lot of grief at a brewery, under what conditions they thrive, and what off-flavours they produce.

Time for Chemistry. Mark reviewed some of the material from yesterday’s lecture concerning hazes, then moved on to beer carbonation. Remember the gas laws we had fun with on Tuesday–putting balloons in the freezer, and opening hot cans of Coke? Well , it was time to learn the theory behind our experiments, and so followed a review of the various gas laws that affect the brewer. (I say “review” because we already have had a fairly exhaustive look at gas laws in Packaging.) We then looked at the various ways of carbonating beer, and their advantages and disadvantages.

Weekend time. Another four assignments to work on, a presentation to begin, and exams only three weeks away…


Day 198

March 30, 2012

Seems that we are a bit behind in Chemistry, so with only three weeks left, Mark Benzaquen gave us a supplementary chemistry lecture in place of our microbiology lab today.

First on the agenda was spectrographic analysis of flavour compounds in beer, specifically with either a spectrophotometer or with a gas spectrometer.

We actually used a spectrophotometer in the lab a couple of weeks ago to measure the amount of iso-alpha acids–the bitterness–in beer. As I recall, the machine was on strike for better working conditions that day, but the way it’s supposed to work is based on the fact that various compounds while in solution absorb light of a certain frequency. If you pass a given amount of light of a single frequency through a solution and measure how much light has been absorbed, you can calculate how much of the compound was present.

A gas spectrometer is way more expensive, but also way more cool–by analysing a compound’s affinity for a gaseous versus a solid state, it not only gives you the amount of a compound in a sample, it also provides you with a molecular “fingerprint”, allowing you to positively identify the exact compound that is present. Very CSI.

Next topic was hazes–what they are, why they occur, and how to deal with them. If you are a longtime lover of beer, you know that from time to time, a beer that should be bright and clear is hazy. Sometimes the haze only shows up when the beer is cold, and disappears when the beer warms up–chill haze. Sometimes the haze is there all the time–permanent haze. Chill haze will, with time, eventually morph into permanent haze, meaning the longer your beer sits on the store shelf, the hazier it will become. Obviously, the more you can do to reduce the compounds that cause haze, the more stable your beer will be over the long term.

(This is probably less of a concern to the brewpub owner who sells all his beer within a week of it being made, but more of a concern if your beer is going to be sitting on a store shelf under a fluorescent light at room temperature for three months. )

Beer hazes can be caused by bacterial infection (eww!), excess carbohydrates, oxalates and excess polyphenol-protein complexes. Since this was Chemistry, not Microbiology, we didn’t deal with the first one in this class.

Carbohydrate hazes are caused by excess amount of either beta-glucans or unconverted starch in your beer. Adding extra enzymes of the proper type to the mash tun should take care of the problem.

Oxalic acid is present in barley that was stressed during the growing season, and shows up in beer as a haze, caused when the oxalic acid forms a crystalline matrix. This matrix also provides a great place for CO2 micro-nucleation sites, so when you open the beer, you instantly get a gushing beer fountain that leaves half the bottle on the countertop and the other half on your clothes. The easy way to get rid of this problem is simply to add more calcium salts such as calcium sulphate to your foundation water–the calcium ions binds with the oxalic acid to form calcium oxalate, an insoluble powder better known as “beer stone” that is left behind in the mash tun.

That leaves us with polyphenols and proteins. In this case, prevention is the best way to fix the problem.

Excess polyphenols come from barley husks, and are in finished beer either because the sparge water that washed across the husks was too hot (more than 80°C), or because the wet grains were excessively raked, turned or otherwise agitated too roughly in the mash tun or lauter tun. So, sparge at 74°C, and be gentle with your grain to avoid the whole problem.

Some protein in beer is necessary–protein forms the walls of bubbles, giving the beer a nice head. Excess protein can be a problem, however. It usually comes from barley that was “undermodified” during malting–large proteins that should have been broken down into amino acid have been left intact. So avoid using undermodified grain–much easier said than done.

So what to do if you have an excessive load of polyphenols and/or proteins? You can’t filter them out, because they start as very small pieces, too small to capture in most filters. Then once the beer has left your brewery, the small pieces join together to form large pieces that cause haze.

There are several steps you can take while the beer is in the brewery:

  • Let some of the protein settle out during maturation, possibly aided by a clarifier such as isinglass (made from fish bladders).
  • Add papin (an enzyme derived from papaya) to break down proteins, then deactivate the papin via heat pasteurization (Don’t use it if you don’t pasteurize your beer–the still active papin will continue to breakdown all the protein in your beer: Goodbye, foam and head.)
  • Add tannic acid just before filtering. Proteins will bind to it and precipitate out. (However, the sediment produced can clog the bottom of your tank, making removal of the beer very slow.)
  • Add a silica gel before filtration. Proteins will bind to the gel matrices, which are then filtered out of the beer. (However, these gels are relatively expensive.)
  • For polyphenols, use PVPP, an agent that binds polyphenols to it. (However, PVPP is expensive. It can be reused, but the equipment required is expensive.)

Lunch. Then back to our lab stools for three hours of Packaging.

Today, the science of the beer bottle filler–the machinery and mechanisms used to get beer from the bright beer tank into the bottle in eight easy steps. (Pre-evacuation of air, CO2, re-evacuation of CO2 and any remaining air, pressurising with more CO2 to same head pressure as bright beer tank, beer bottle filled, pressurising with CO2 to force any excess beer back up filling tube, depressurising bottle to atmospheric pressure, and finally “snifting”–lowering bottle away from beer filler head while using a jet of CO2, a small jet of hot water or knocking the bottle to produce enough foam to displace any air in the neck of the bottle until the bottle can be capped a split second later.

Another five-hour day on a lab stool. I ain’t gonna sit down for the rest of the day, at least not without some serious padding.

Day 197

March 27, 2012

Last night, CBC aired the third episode of a new show called The Big Decision. The premise of the show is that a business in big trouble seeks an investment from Canadian business tycoons Jim Treliving or Arlene Dickinson.  In last night’s episode, Dead Frog Brewery of Aldergrove, B.C. had run into a big financial mess. At one time the craft brewery had sales of several million dollars, but rapid expansion, equipment breakdowns, a bad batch of beer that had to be recalled and poured down the drain, and lack of marketing had put them into a cash crunch. When Jim Treliving visited, he found a small brewery that was producing no less than ten different beers, using an inefficient packaging line and warehouse that had been bodged together rather higgledy-piggledly. Before Jim decided whether to invest $500,000, he insisted that within two weeks, the brewery cut back to only four different beers, reorganize its production line and warehouse, design a new marketing campaign, and come up with a business plan and financial statement.

I won’t reveal how the brewery responded to the those challenges, or what Jim’s eventual investment decision was, but I was intrigued. These problems–or rather, how to avoid these problems–have been the focus of several different courses this semester:

  • Avoiding infection problems: Microbiology, Packaging, Equipment, Practical Brewing
  • Preventative equipment maintenance program: Equipment
  • Efficient packaging line: Packaging, Equipment, Practical Brewing
  • Marketing, business plans and financial statements: Strategic Communications

Of course I’m not saying that we Brewmaster students will avoid these problems, but I was fascinated that so many different instances of classroom theory can be seen in one real life case study.

As a big “for instance”, we talked about designing an orderly, efficient and sanitary packaging line in Brewing Equipment today. A veritable confluence of events. Neat!

In Chemistry Lab, although our experiments were linked to the gas laws that govern beer packaging, they were done with tools we could find around the house. At one point we simply inflated two balloons and put one of them into the freezer. When we took it out a few minutes later, lo and behold! the balloon had shrunk to about half its original size. Not exactly rocket science, but a perfect demonstration of Charles’ Gas Law, which states that the volume of a gas will decrease as its temperature decreases. (Or vice versa: the volume of gas will increase as the temperature increases, which you can demonstrate by leaving a case of beer in your car trunk on a really hot summer day. But be sure to use beer you don’t care about, and don’t leave any good clothes in the trunk either.)

Likewise, taking one can of Coke and putting in the fridge, then taking a second can of Coke and putting it in hot water will quickly demonstrate Henry’s Gas Law: the solubility of a gas decreases as the temperature increases. Or to put it another way, the cold can of Coke, even when shaken, opened with a simple and undramatic whiff  (because the CO2 stayed dissolved in the cold Coke), while the hot can, upon being opened, sprayed the unlucky volunteer with foam (because the CO2 refused to stay dissolved as the temperature of the Coke increased.)

At least it wasn’t beer that was wasted.


Day 196

March 26, 2012

Today was actually our last lecture from Prof. Sandra Merks in Strategic Communications—for the last three weeks of the semester, we will be making our business plan presentations to the rest of the class.

Today was about the importance of making proper attributions in our reports—in other words, giving proper credit for using other people’s work, and making sure the attributions are in the proper format. Then on to what you call it when you don’t properly credit your sources: plagiarism.

And here’s something I did not know: I can plagiarize myself. If I re-cycle an essay or report I might have previously written–say, in high school or university—that would count as plagiarism. Huh.

Not that I think my old essays about John Mills and utilitarianism or themes of facial disfigurement in CanLit are going to help me write a business plan.

Day 193

March 23, 2012

Last week in Sensory  Evaluation, my taste buds were on some kind of holiday. This week, they were clearly back on-line, as I had no difficulty distinguishing four more off-flavours: 3-methyl-4-butyl-5-thiol (MBT or “lightstruck”), hydrogen sulphide (rotten eggs), oxidation and sour infection. As a matter of fact, I didn’t actually have to taste any of the off-flavour beers–I was able to distinguish all of them by smell alone (especially the hydrogen sulphide–whew!

On the plus side, a classmate gave me a bottle of Samuel Adams Dark Depths Baltic IPA, which I shared with the class–an excellent way to remove the memory of today’s off flavours from our taste buds.

In Chemistry and Microbiology, it was mainly a review of the formation of amino acids, oxo-acids, diacetyl, sulphurs, aldehydes, fusel alcohols and esters during fermentation, but we also went into more detail today about how to encourage or discourage the production of each of them.


Day 192

March 22, 2012

Sometimes there might be some obnoxious microscopic critters swimming around in your beer, but if none of them happens to be swimming in the single small droplet that you pull from the beer, then you will never know. In Microbiology Lab today, we made our chances of discovering bad critters a hundred times better by taking a 100 mL sample of beer, then using a vacuum pump to pull the beer through a sterile filter pad, thereby trapping any critters on the filter pad. We then plated the filter pad on agar medium in a petri dish to see if anything would grow.

We enjoyed the mildest winter on record in southern Ontario, and spring has continued in the same vein. Today in particular, the thermometer soared to 26°C (80°F), the warmest March day ever recorded in this area. Now you might think that this would be a good time to sit outside on the student pub patio with a glass of cold First Draft Campus Ale. And you would be right. But then someone pulled out a frisbee, and minutes later, there we were, shoes off, bare feet on warm grass, running after errant throws.

(Yes, if you sat in an office today when you’d rather have been drinking cold beer and running on grass barefoot catching a frisbee, the previous paragraph was for you.)

However, inevitably lunch hour came to an end. Doug Pengelly brought a special guest to Packaging, Bryan Maher of Wellington Brewery. Bryan runs the canning line at Wellington, so today he explained how a canning line works, as well as the maintenance issues and various fun things that can go wrong at the most inappropriate time.

(Best comment from Bryan: “You’re guaranteed to have a beer shower at least once a day. That isn’t as cool as it sounds.”)

Then it was back into the heat and sunshine, if only for the drive home. Probably the first time I’ve ever had the car’s air conditioning on in March.

Day 190

March 20, 2012

In Brewing Equipment, we learned more about the thought processes that go into the programming necessary for automation. It goes like this: a well meaning programmer who has no knowledge of brewing comes to you and says, “Hey dood, I can create a program to automate your <insert piece of brewery equipment here>. Just tell me what processes are used.”

You then sit down and describe exactly what valves open or close and what motors turn on or off, and for how long and under what conditions, and in what order. Or make up a graphical interface that shows the programmer what processes are used for each sub-process of the process.

Although this sounds easy, consider the steps needed for even the simplest things we do without even thinking about it–say, finding the mash temperature is a bit low and supplying some steam to the mash tun:

  1. [Input from temperature sensor] The mash temperature is too low!
  2. We need steam! Open the steam valve! Turn on a panel light to let the operator know!
  3. [Input from temperature sensor] Is the mash temperature correct yet?  If no, repeat Step 3. If yes, close the steam valve and turn off the panel light.

It sort of reminded me of days of yore creating BASIC programs on my Commodore 64.

Our next assignment is to choose a piece of brewery equipment and create the list of processes that a programmer would need to know in order to create an automated program.

Maybe I should go and hunt up my old C64–I’m sure it’s in the basement somewhere.

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