Vacation time!!!!

Posting will be slow around here for a while. I am off on vacation with the family.

Hopefully, it won't end like:

Back in a week...

Brewing chemistry: Part 3- Mashing: Amylase

Once the barley has been malted and roasted, the grain is full of starch and enzymes. The grains are then dried and roasted. At his point, it is critical that the amylase enzymes not be denatured. Denaturation is any process that renders enzymes inactive. Heating (i.e. cooking) will denature proteins (enzymes are proteins). Roasting the barley too hot could destroy the critical enzymes. But, fear not, the folks who do the roasting know exactly what they are doing.

When the barley is roasted it is ready to be mashed. For extract brewers, this is something that isn't done. For all-grain brewers, mashing is a critical process. A screw up here and the whole batch could be ruined. Mashing essentially breaks up the starch into fermentable sugars. No sugar, no beer.

As I have mentioned before, I am now doing partial mashes (I'll post later about my method). In fact, all four batches featured recently were partial mash batches.

There are a lot of things that happen during a mash. I will focus on the action of amylase in the context of doing a partial mash.

During mashing, malted barley is heated in water. For partial mashing about 1 liter of water is used per pound of grain. The temperature control is critical since the amylase activity is dependent on temperature.

There are two main amylase enzymes at work. The enzymes are formed during the malting process thanks to the action of gibberillic acid. The two enzymes are alpha-amylase and beta-amylase.

They both break glycosidic bonds between the glucose molecules in starch. However, alpha-amylase does so randomly and beta-amylase starts at the end of the starch chain (the non-reducing end) and chops off two glucoses (maltose) at a time. The optimum temperature for alpha-amylase activity is around 158° C and that for beta-amylase is around 145°C. In all grain brewing temperature control is absolutely critical since the amylase activities must be balanced out. In partial mashing a temperature compromise is reached. At 152-154°C the activities of both enzymes are good enough to result in decent conversion.

The goal is to not convert all of the starch into glucose or maltose. Unless you are trying to brew a very dry beer with very low residual carbohydrate levels (i.e. T.A.L.L.). If beta-amylase activity is allowed to dominate, the result is a highly fermentable wort and a dry beer.

A great description of partial mashing is available on the BYO website

10,000 page views!!!!

OK, probably 85% of them are by me, but this simple little blog has just been viewed 10,000 times. Not bad for a blog that doesn't really say anything. Of course it is about beer.

Finally, my pipeline is full

With the end of semester craziness and beginning of summer craziness, my beer pipeline nearly dried up. I recently remedied this.

Behold, my brewing beer:



From left to right: bitter, pale ale, India pale ale, and honey wheat.

Another angle:



The bitter is in the secondary and the others are in their primaries.

Lord Stanley's Mug

I was driving home from Home Depot with 85% of the items I needed to install a toilet in my partially finished basement when I heard on the radio something I had totally forgotten. The Stanley Cup was coming to my town.

For those of you who don't know what the Stanley Cup is...shame on you. It is the trophy given to the National Hockey League championship team. It is easily the most historic trophy with the most tradition. When won, each player on the winning teams roster gets to spend 24 hours with the trophy. They can do almost anything they want with it. Most take it "back home" and show to friends and fans.

Ryan Carter was a member of the championship Anaheim Ducks. He was also from White Bear Lake, Minnesota and played his college hockey at the local university in my town. He brought the cup here today.

I got to the event right at noon after running home to quickly grab a camera. I situated myself about 15 feet from the table and waited for the cup to arrive. After waiting almost an hour, I decided "screw this, I have a toilet to install." So, I left. On my way out, I decided to wait outside for 5 minutes. During that time, the cup arrived.

I was close enough I could have spit into it. It was pretty cool to see the most hallowed sports trophy in person.

Here are some pictures. I took all of them myself. I would have taken more, but my batteries died. After taking these pictures outside, I left and installed my toilet. It works.

The eagle has landed!!!

Fat Tire is here in God's country[1]. I know of one location in MN (Surdyk's in Minneapolis) that has it. There may be other locations that I am not aware of.

Hopefully, Fat Tire will spread like a virus in MN.[2] If not, Surdyk's will be a routine stop on my beer supply trips to the Small Apple[3].

[4]



[1] this claim is open for dispute
[2] in a good way, of course.
[3] Minneapolis
[4] Image lifted from the New Belgium brewery website (drink their beer, if you can find it)

Beer is bad? NEVER!!!! OK, maybe

A lot of chemistry blogs (many of them are very good) include updates from the literature. These are papers that are important in certain fields or just interest the blog author.

Recently, one of the (eh-um) "journals" I read had an interesting article about a dangerous chemical in beer. OK, the "journal" is Brew Your Own magazine, but it was still a well written and interesting article.

I'm a big fan of BYO magazine and BYO.com. It is a great publication for those of us interested in learning everything we can about our favorite hobby.

The article was part of the "Help Me, Mr. Wizard" feature. The articles in BYO magazine are great, but the "Ask Mr. Wizard" feature is my favorite. Mr. Wizard, Ashton Lewis, knows what he is talking about, but (and this is most important) he also researches what he says.

In the latest issue (which I have read completely and will proceed to read again), Mr. Wizard was asked about the dangers of tyramine in beer and the differences between draft beer and bottled beer.

For the most part, Wizard Lewis doesn't shy away from technical terms, but there is nary a chemical structure to be seen. That's OK. That's where this blog comes in.

Tyramine is formed when the amino acid tyrosine is decarboxylated by some bacterial enzymes, namely lactic acid bacteria.



Tyramine is not a problem for most people since monoamine oxidase enzymes catalyze the metabolism of tyramine. However, people taking monoamine oxidase inhibitors (MAOI) have difficulty dealing with tyramine.

The result is high blood pressure and possibly a stroke.

The Mr. Wizard response goes on to explain that tap beer has a higher chance of containing dangerous amounts of tyramine. Commercial bottled beer has a nearly zero risk thanks to pasteurization. Kegged beer and homebrew beer are not pasteurized and run the risk of harboring the offending bacteria.

Tyramine is also found in other foods.

The bottom line is avoid tap beers and homebrew if you are on MAO inhibitors.