Archive for February 2012

Day 165

February 24, 2012

Mid-term madness is over!

The winter storm that had been threatening yesterday materialized as cold rain. The Sensory Evaluation mid-term therefore went ahead as scheduled. It was a very do-able exam if you had paid attention in class. (Apparently I had, since I found it very do-able.)

Back at home, I finished an on-line assignment for Strategic Communications, and gleefully checked it off as the final item on this week’s list of tests, exams and assignments. Three mid-terms, two tests and two assignments finished; zero to go.

This officially marks the start of Reading Week: nine consecutive days where I must daily force myself to have another cup of joe whilst reading the newspaper in my pyjamas.

 

Day 164

February 23, 2012

We silently gathered outside the classroom. With a collective sigh, we entered. It was time for the greatly feared Microbiology mid-term. Vacuoles. Saranin-O. Cytoplasm. Anaerobic. Chitin. Mitochondria. Flocculation. And that was just page 1.

Ouch.

On to Packaging and a quick “fun quiz” before we started to talk about balancing draught lines. However, we’d barely started when word came that we were all invited to a special presentation from PEI Brewing, a new start-up in Charlottetown looking for a few eager young brewery workers. End of class and end of the day.

So, one last mid-term to go tomorrow, if an approaching winter storm doesn’t intervene.

Day 162

February 21, 2012

Pumps.

As you may recall, a few weeks ago, it seemed like we were learning about, drawing, researching, writing about, eating breathing and drinking nuthin’ but pumps. I was starting to see pumps in my sleep.

(A recurring nightmare: I am sitting in a small room at a desk covered with machine parts. A disembodied voice says, “The parts of a disassembled 1 hp centrifugal pump lie before you. In five minutes, a hungry mash tun will be admitted to the room. Take any actions you deem necessary, document them, and be prepared to justify your actions.” I always awake in a cold sweat.)

So understand my fear and loathing in Brewing Equipment today when Gordo Slater scrapped the scheduled test on boilers, cooling systems and mash tun design, and instead handed us a blank sheet of paper with the instructions, “You’re a brewmaster on vacation. You’re lying on a beach when your cellphone rings. It’s the shift brewer with news that the centrifugal pump that is supposed to move the mash from the mash tun to the lauter tun isn’t working. Describe the conversation.”

My first instinct was to write: “Fix it, dude.”

Meh. Probably not a lot of marks there. So I carefully describe a trouble-shooting conversation: “Is the pump running? If not, is it plugged in? Turned on? Is the circuit breaker open? If it is running, is…” Etc.

Damn pumps.

After that little exercise, we looked more closely at lauter tuns. As we learned in first semester, the lauter tun is where you separate the wort from the grain as efficiently as possible. Now we’re starting to get into the nitty gritty of these pieces of equipment. What is the maximum load of mash per square metre? What is a batch lauter? (As compared to a flying lauter?) What are the advantages of each? What is the maximum depth of grain bed, and how does that change the aspect ratio of your lauter tun? What are the pros and cons of a wedge wire false bottom versus a machined steel false bottom? How do you calculate the efficiency of your lauter tun? (That is, if you put in so much grain that has a potential amount of extract to be drawn from it, how sweet is the wort that is leaving–in other words how much of that sugar did you manage to get?)

On to our second test of the day, the Chemistry mid-term. Fifty questions, most requiring some thought. However, I think I passed.  And I handed in the media kit assignment for Strategic Communications.

So that’s one major assignment, one test and one mid-term exam done. One test and two mid-terms to go.

 

Day 159

February 18, 2012

For the past few weeks in Sensory Evaluation, we have been looking at setting up tasting panels and the types of tests that can be used. Today we looked at open and blind tests. An open (non-blind) test is where both you the tester and your subject(s) are aware of the beer being tested.  This might be used for your brewery’s daily quality control check tasting–everyone knows the beer you are tasting, you are only interested in finding out if a problem has cropped up in the latest batch of beer.

Then there is the single-blind study: you know what beer is being tasted, but your panelist only sees glasses coded with “Sample A”, “Sample B”, etc. This works well if you are able to refrain from passing on info to the taster through speech intonation or body language–for instance, unconsciously sighing and rolling your eyes as you hand your panelist a sample of something you believe tastes like water (or worse).

To prevent this, there is the double-blind study: neither you the tester, nor your panelists know which beers the panelist is tasting. First you need to have a “cut-out” person who sets up the samples for you, marked by codes, and then leaves. When you arrive, you have no idea what you are serving–only the cut-out person holds the “key” to which samples are which. A double-blind is less frequently used, simply because it is more complicated to set up and run.

Once you have run your tests, you need to be able to turn the raw data into results. Instructor Mark Benzaquen quickly ran through some very basic statistical principles (that still left left me scratching my head at times. Stats were never my strong suit in math class.) However, Mark did mention that there were spreadsheet programs available that would analyze your data and deliver a summary of results. (“I’ve got to find me one of those!” I thought to myself.)

Okay, so you’ve run the tests and you have results. Lastly, you need to be able to communicate the results of your tests to your client–no use in organizing a tasting panel and running a bunch of tests if the results just sit in a folder on your desk.

On to Chemistry. Today, it was all about enzymatic activity during the mash. First of all, what is an enzyme? Let’s start small, with a measly little amino acid–a standard structure in the chemical world that has an amine group (nitrogen and some hydrogens) and a carbon group (some carbons and oxygens), both joined together like the two wings of  a capital “T”, with another group of molecules joined to them like the downstroke of the T.

The last group of molecules varies from amino acid to amino acid, and defines the amino acid’s function. Think of amino acids as Swiss Army knives–every Swiss Army knife has a red case–the amine group–and a fold-out knife blade–the carbon group. It’s the other fold-out tools like screwdrivers, nail files and scissors–the third group of molecules– that varies from model to model and defines how a particular Swiss Army knife can be used.)

Now, put two of these amino acids together and you have a peptide. Put many peptides together and you have a protein–a structure that is dozens if not hundreds of molecules long. Some of the atoms in that structure have negative or positive charges, and the attractions and repulsions of the various atoms and molecules start to bend the molecule chain this way and that, resulting in a very abstract-looking collection of helixes and wavy bits. However, if you heat up a protein too much, the energy unwinds this unique shape, and possibly even breaks up the protein into its component peptides and amino acids.

Okay, so what is an enzyme? An enzyme is a protein that acts as a catalyst, breaking apart or joining together other molecules, while remaining unchanged by the chemical reaction that it has enabled. For instance, an enzyme called beta-amylase can attach itself to the end of an amylose starch chain and break off a maltose unit (two glucose molecules). Then it reattaches to the chain and breaks off another unit… and then another and another, until the chain has been completely broken up into maltose.

Various enzymes with various tasks are designed to operate most efficiently at various temperatures and pH concentrations. The purpose of the mash is to provide the proper temperature and pH for several enzymes so that they can break down the proteins and starches in the barley kernels into sugars and other substances needed by the yeast.

Whew. That was something of a review of concepts we had covered last semester in Ingredients, but more quickly and in more detail.

On to Microbiology. The topic was how to crop yeast–that is,  how to save some yeast from a batch of beer that has finished fermenting and immediately use it to start another fermentation.

Why immediately? It turns out that yeast has an internal energy supply called glycogen. If you haul the yeast out of the fermenter but then leave it sitting in a bucket for a few days, the heat of the room and the oxygen in the air will kick-start yeast growth, forcing the yeast to use its glycogen reserves. When you go to use it, your yeast won’t have the energy reserves needed to get the fermentation process going. Good luck with that beer thing.

Of course, leaving the yeast in the fermenter after it’s done fermenting is just as bad–the yeast is actually being poisoned by the alcohol and carbon dioxide that the yeast itself made. Leave it in the fermenter, and the yeast will build a kind of armour to protect itself–which again will use up its glycogen reserves.

So get your yeast out of the old fermenter as soon as fermentation has ended, and immediately get it back to work in a new batch of wort. If you do have to store it for a few hours or days, remove the CO2 from the slurry (with gentle agitation), then put it in a fridge, and protect it from oxygen.

That was it for the week. Thankfully it is a long weekend in Ontario–and that extra day will come in handy for studying. Even though next week is only 4 days long, we have 3 mid-term exams and 2 tests scheduled, and one major assignment due. I sense this is one long weekend where I  will be cracking open more books than beers.

Day 158

February 16, 2012

Sam Corbeil brought some beer to Microbiology Lab today. Not the kind you would want to drink (unfortunately), but the kind that had been left in a forgotten cask at room temperature for several weeks: a funky-smelling evil-looking cloudy orange liquid with a thick sludge at the bottom. This gave us an opportunity to try to ID the little critters that had turned it to the Dark Side.

Using a miscroscope

Hunting for critters--baseball hat optional

First we took a sample from the very vinegary, cidery smelling liquid and prepared a microscope slide. Looking at the invaders at 400x magnification, we could see both rod-shaped and cocci (round) bacteria.

Next we stained another slide with ammonium oxalate, Gram’s Iodine solution and Safranin-O. Any bacteria that appeared blue or violet under the microscope were “Gram-positive”, any that turned red or pink were “Gram-negative”. In this case, they were all Gram-negative.

Finally we dropped some hydrogen peroxide onto them to detemine if the bacteria were catalase-positive (bubbles form) or catalase-negative (no bubbles.) Our sample was catalase-negative.

With all the evidence at our disposal, we narrowed the field down to either an acetic acid bacteria or some form of acetomonas.

In Packaging, we continued our examination of draught systems by taking apart a keg and then taking apart the keg’s spike–the long metal tube in the keg that sucks up beer.

We also looked at other pieces of the draught system, including multi-keg dispensing tubes, couplers, and the F.O.B. (Foam on Beer), a useful device that detects when your keg has run out of beer and is dispensing nothing but foam.

Then we went on a field trip–all the way to the campus beer store, where we examined the store’s draught system set-up. And while we were in the store, it seemed like a good idea to sample the beer on tap. Best. Field Trip. Ever.

Day 157

February 16, 2012

In the Teaching Brewery today for the first time in three weeks. Four of us using two of the 50L pilot systems brewed up a double batch of “Nude Brewing Brunette”, a sweet brown ale made with Maris Otter, Carafoam 60, Brown and Midnight Wheat malts, with a very modest addition of Pilgrim hops.

Boiling wort

Nude Brewing Brunette on the boil

Things went okay–we had to deal with a shortage of hot water in the brewery, as well as some of the other unexpected problems that crop up during a brew day–but the biggest problem was that the original gravity of both batches was a lot higher than expected–1.056 rather than the expected 1.032. However, since this happened to both brews, the problem probably has to do with the recipe rather than us making the same mistake with both batches. Probably.

[Digression for non-brewers: specific gravity measures the density of the water. The more sugar dissolved into the water, the higher the density of the water. Yeast converts sugar into alcohol, so the higher the starting specific gravity, the more sugar there is for the yeast to eat, and therefore the stronger the final beer. Brewers measure the specific gravity of their beer at the start of fermentation (the “original” gravity) and at the end of fermentation (the lower “final” gravity.) The difference between these two numbers represents how much sugar the yeast ate–the brewer can then calculate how much alcohol is in the beer.]

Since we weren’t planning to brew a high-octane barleywine, we creatively solved the problem by diluting the wort with a few litres of water in order to bring the original gravity down to its intended level.

And then we went for a beer.

Day 156

February 15, 2012

If you walked into a brewery 150 years ago, you would have seen a lot of copper or wooden vats. Today, stainless steel is the hands-down winner in most breweries because of its easily cleaned, corrosion- and chemical-resistant surface. As we learned in Brewing Equipment, stainless steel is an alloy of steel and at least 11% chromium. By varying the amount of chromium and perhaps adding a few other ingredients like carbon, molybdenum, nickel, and manganese, various grades of stainless steel can made more ductile, more durable, shinier, easier to engineer, resistant to pitting,  non-magnetic or even resistant to seawater corrosion.

The reason we were learning about stainless steel was because it is time to take a very close look at each component of the brewhouse, starting with the mash tun. We had looked at brewery equipment last semester in Intro to Brewing, but today’s examination was less about what each piece of equipment does, and more about the various design features we will need to keep in mind in the future as we shop for–most likely “pre-owned”–brewery equipment.

So for the mash tun, we looked at the design of the steam jackets–the tunnels inside its walls through which hot steam travels–as well as the insulation used to keep that heat focussed inwards. Believe it or not, Fiberglas Pink is not the insulation of choice for a mash tun.

We also looked at the aspect ratio of a mash tun, the placement of the mash-out drain–not in the very centre of the mash tun floor, to prevent whirlpooling like what you see when your bathtub drains–and the agitator arms that an automated mash tun uses to mix up the mash.

Speaking of automation, we have also started to skim the surface of an automated or semi-automated brewery operation–the logical flow of procedures and error checking to make sure everything is happening properly.

It’s kind of like the old flowcharting we used to do way back in the day:

  1. Open bottle
  2. Pour beer into glass
  3. Take swallow of beer
  4. Is your glass empty? If yes, go to 1, otherwise go to 3
Hey, this automation could be fun.

 

 


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