Day 148

After the “Caps, Corks & Forks” dinner last night, and the socializing that followed, 6 a.m. came earlier than usual. Or at least it felt earlier than usual.

In Sensory Evaluation, we learned more about sensory panels. What is the purpose of your panel? How many panelists will you need? How should you select your samples to be tasted? What temperature should the samples be at? What type of pitcher should the samples be poured from, and how should the sample be presented? How many samples should the panel taste at one sitting?

Then we looked at panelists. What makes a good panelist? (Being in good mental and physical condition was top of the list. I knew beer drinking was an athletic sport.) And how we would go about choosing panelists?

The answer to that last question was surprisingly long:

  1. Find 5-6 times as many volunteers as you think you will need from all parts of the brewery.
  2. Interview the candidates and explain what this is all about. —Eliminate anyone who:
    • doesn’t like beer (duhh!)
    • doesn’t drink beer due to cultural or religious issues
    • can’t drink beer due to allergies or medication
    • won’t be available on the day(s) and time(s) the panel will be held
  3. After an orientation session to tell them how the panel works, move on to the testing. Give the candidates several glasses of carbonated water that have been spiked with various basic flavours (i.e. salty, sour, sweet, bitter). Give them a second set of the same samples again but in a different order; ask them to match the same tastes from set A and set B. Eliminate anyone who can’t do this–if they can’t differentiate the four basic tastes, their ability as a taste panelist is limited.
  4. Give the panelists three identical taste samples, except one has been spiked with an off-flavour. Ask them to identify which one is different.
  5. Train the candidates to identify a particular off-flavour. Then give them several glasses of one beer to which increasing amounts of the off-flavour have been added. Ask them to rank the glasses from least to strongest in terms of the off flavour. Eliminate any candidate who doesn’t get at least 60%.
  6. After further training about defects, present a set of samples illustrating  5-10 flavours/defects typical found in beer samples, one at a time and ask them to describe their responses. Eliminate any candidate unable to successfully describe 5 or more.

There. Anyone who is left is now a part of your tasting panel.

In Brewing Chemistry we reviewed some of the information we had rapidly processed two weeks ago, especially the role that alkalinity (water softness) plays in brewing. Water softness is caused by ions called carbonates. Here in the Niagara region, we are literally right next door to the 700-kilometre limestone ridge called the Niagara Escarpment. Limestone to a chemist is calcium carbonate, and the chemist will tell you that having all that calcium carbonate in your mash is just plain bad news. Due to a series of reactions that I won’t list, carbonates remove calcium ions from your mash–calcium ions that will be needed by yeast during fermentation–and will also remove hydrogen ions, driving up the pH of the mash. (Low pH is needed for proper enzyme action in the mash tun and proper yeast growth during fermentation.)

The way to deal with high alkalinity is to add calcium salts or magnesium salts such as calcium chloride (gypsum) to your hot liquor before mash-in. There were a bunch of reaction equations to prove this would work.

Then we moved on to the chemical composition of barley. We had done a bit of this in Brewing Ingredients last semester, but we went into much more detail now: cellulose’s beta-1,4 bonds, pentosan’s exotic beta-1,3 bonds, proteins, polypeptides, cascades of enzymes to break down protein and starches. I tried to stop my brain from leaking out my ears as we switched to Microbiology

where we learned more about yeast then we thought possible. Mutations–random and engineered. Forced genetic recombination. DNA mapping. Polyploidal genes.

If it’s Friday afternoon, it must be time for my head to explode. Again.  

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