Friday, June 29, 2007

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.

Saturday, June 23, 2007

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].


[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)

Friday, June 22, 2007

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 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.

Friday, June 15, 2007

Science Camp: Day 4

Day four, the final day.

One thing I have learned is that running a Science camp or any camp for 5th to 8th graders is exhausting. By the last day, I am running on fumes.

On the last day, we started by finishing their egg drop devices. They had an hour to finish, test and weigh in their devices. From there we moved to the separate sections.

In chemistry we analyzed the stained DNA agarose gels. We found out suspect 3 was guilty. We promptly sent him off to the death chamber.

Then we synthesized aspirin. 0.5 grams salicylic acid plus 1.5 mL acetic anhydride and 3-4 drops phosphoric acid. Heat at 80°C for 5 minutes. Add water and cool. This is a bit of an advanced lab, but they seemed to enjoy it. The underlying beauty hidden on the molecular level escapes them, but it is cool to see white crystals form from a clear solution.

The demo of the day was gummi bear oxidation and thermite. The gummi bear oxidation was done by adding gummi bears to molten potassium chlorate (KClO3. it shoots off some nice flames.

Thermite is the reaction of iron (III) oxide and aluminum metal. It produces molten iron as a product. This time I did my biggest one ever. I used about 1.3 kg of iron (III) oxide and 400 g of aluminum. It took a few attempts to ignite and it worked almost great. I say almost because some of the mixture got blown out of the flower pot holding it before it got a chance to react.

I promise to show a video of this once I find that stupid firewire cable for my video camera and can load it onto my computer. I've looked everywhere. Does anyone know where I put it?

We ended the camp with a picnic for the campers and their families. We had about 100 people show up. We started with the egg drop competition, then we ate, had a small awards ceremony, and that was it. Science Camp was over.

Time to start planning for next year.

Yeast from a bottle

In comments to a recent post on my plans for doing partial mash brewing, a-non-y-mous and Joe wanted to know how I recover yeast from bottles of beer.

Well, it's quite easy actually.

I first make a typical yeast starter. I usually boil about 1/4 to 1/2 cup of dry malt extract in about a quart of water. After cooling, I add it to a sanitized half-gallon bottle and affix a sanitized airlock.

Here comes the really hard part. I drink a bottle of beer made from the yeast I want to reculture. OK, that's a lie. I usually drink 2 beers. No, that's a lie too. Typically, I drink 4 of them. The truth is, the yeast from one bottle is enough to reculture, but why not give it a head start. Beside, the beer is good.

I pour out 10 ounces of the beer into a glass (and drink) and sanitize the neck and lip of the bottle. I swirl the remains of the beer and simply dump the yeast slurry into my starter. I repeat for any subsequent beers.

That's it. If fermentation starts and bubbles form by the next day, you are in business. Proceed as usual.

Sometimes you can refrigerate the yeast for use at a later date.

The beauty of this procedure is that it saves about $5 per batch. That can be about 15-20% of the cost for a batch.

I have 5 batches planned for the next month. Of those 5, I only needed to buy one yeast strain (Wyeast 1968 London ESB Ale yeast for a bitter I want to make). The most common strain I reculture is good ol' Wyeast 1056. I only reculture for 4-5 generations. After that I start with fresh yeast. Though, I've never noticed a difference between the fresh and recultured yeast.

Science Camp: Day 3

I'm a bit behind in my updating of Science Camp 2007. It is actually done, but I have two updates to make. I also can't find my firewire cable that connects my video camera to my computer. I have some video I want to upload, but unless I find that cable, nothing will be uploaded. Oh, well. I'll worry about that later.

Day 3: We started out day 3 with what we call, Egg Drop Engineering (EDE). The task is to protect an egg from a 5 meter drop. The old classic activity, but one they enjoy. There are scored on whether the egg breaks or not, the number of pieces, the mass of the device, and the accuracy of hitting the target. The twist was that each camper was told to bring 2 items that could be used and they would randomly organized in groups of 3. This meant, they had no idea who their partners were or what they were going to have to work with. They spent about an hour designing and building. The actual drop will occur tomorrow.

They split up into the three groups for the rest of the day. In chemistry, they loaded their DNA fragments from the forensic DNA analysis onto agarose gel. This was very entertaining for me. Visualize 30 5-8th graders trying to pipet 20µL into a tiny well in an agarose gel. Most of them did pretty good. Some did not. The 100 volts of electricity was applied for an hour. On Thursday they will make a verdict after I stained the gel.

During the remainder of the chemistry time, we did some cyanotyping. Cyanotype is like making a blueprint. A piece of watercolor paper is coated with a solution of potassium ferricyanide (K3Fe(CN)6) and ferric ammonium citrate (Fe(NH4)C6H8O7) to produce the photosensitive compound, iron (III) hexacyanoferrate (III), Fe[Fe(CN)6]. When this paper is exposed to light, the ferric ion (+3) gets reduced to ferrous ion (+2). The ferrous ions then react with the ferricyanide ions of the potassium ferricyanide to produce ferrous ferricyanide (Fe3[Fe(CN)6]2. This blue compound is insoluble in water, but the yellow iron (III) hexacyanoferrate (III) is soluble. In this activity an opaque object in placed on the paper and the paper is taken outside and exposed to sunlight. The solution under the opaque object is then washed away leaving the blue negative.

The demo and snack of the day was liquid nitrogen ice cream. They loved it. I ended up making almost one gallon of ice cream.

Wednesday, June 13, 2007

Science Camp: Day 2

I never got around to posting this last night, so it's a little late.

Yesterday, Day 2 of Science Camp, was another fun day. We started by finishing up the insect collecting. After about an hour of terrorizing butterflies, we moved to individual sessions.

In the chemistry session we did some DNA testing. For convenience I use a forensic DNA fingerprinting kit from BioRad. I've used this kit several times and it has always worked. I spread it over two days.

During the first day, I talk about DNA and how restriction enzymes can be used to make distinct DNA fragments. To illustrate this, I give them a strip of paper that has been subdivided into 40 boxes. I give them each a box of four crayons (like the ones you get a restaurants to entertain the wee ones until the food arrives). They are instructed to randomly color the boxes with the four different colors. Ideally, each color is used for 25% of the boxes. After they are done coloring, we get out our restriction enzymes: scissors. I pick a sequence of colors at random and anyone with that sequence cuts the "DNA" with the scissors. For example, I pick "red, blue, blue." Anyone with that sequence would cut after the second blue. Next we switch to a different enzyme that cuts after the sequence "Green, Yellow." Anyone with the sequence would cut after the yellow box. This continues for a few more rounds. Eventually, we compare everyones "DNA" fragments. I've never had anyone get the same # and size of fragments. It illustrates the point that everyones DNA is different and different fragments will be formed when the restriction enzymes are used.

After the coloring exercise, we went to the lab to add the EcoR1/Pst1 restriction enzyme mixture to DNA samples. There was a crime scene sample and 5 suspect samples. To do the transfers we use Eppendorf micropipets. A lot of time is spent teaching them house to use the pipets, but they love using the professional tools. They are closely supervised of course.

After the restriction enzyme has been added to the DNA it is incubated overnight. On Day 3 of Science Camp we will do electrophoresis.

The demo of the day involved the combustion of hydrogen balloons. This has been one of my favorite demos since I first saw it done at the University of Nebraska. The first balloon contains pure oxygen. A candle on the end of meter stick acts as a igniter. The pure oxygen balloon simply pops and the crowd is not amused.

What's the problem? There is no fuel, just oxygen.

The next balloon contains hydrogen. The candle on a stick is place under the balloon and boom! This amuses them a little more. Now that there is fuel, the "boom" is nice. However, the only source of oxygen is on the outside. The balloon must pop first, mix with the hydrogen and then combust.

The final balloon contains 2 parts hydrogen and 1 part oxygen. The candle is placed under the balloon and BOOM!!!! The blast is felt and heard by everyone near. Now we are talking chemistry.

It illustrates the importance of stoichiometry.

As an added bonus, I tried something I always wanted to try. I taped 5 hydrogen balloons together in a line. I put the candle under the first balloon and the chain reaction worked even better than expected. Oddly enough, the sequence of explosions had the rhythm just like the first part of "shave and a hair cut..." It was weird.

I didn't video tape it, but I am going to repeat that and tape it for sure.

Tuesday, June 12, 2007

Pseudo all-grain

In a distant blog far, far away, a-non-y-mous suggested I start the summer off right and go all-grain. Great idea, but for a variety of reasons now is not the time.

However, I am going to trade my tricycle (extract brewing) in for a two-wheeled bike with training wheels. I am going to start doing partial mashes.

In extract brewing, 90-100% of the fermentable sugars come from malt extract. This source is very convenient and makes great beer. In all-grain brewing, all of the fermentable sugars come from the malted barley. While this beer is also great (and not necessarily better), there are more subtleties involved with all-grain beer that take the art of brewing to a much higher level. Partial mashing is a combination of the two, though more closely associated with extract brewing.

In partial mashing, some of the sugar comes from grains and the rest comes from extract. It is an easy transition to make since the only additional piece of equipment needed is a beverage cooler (and that's not even critical).

I am planning a future post on the actions of amylase during mashing, so I will save the science for later. The general procedure (and I have not actually done this yet) is to add the grains and water at 155° F to the cooler and let it sit for 60-90 minutes. The liquid is drained off and added to the brew kettle. Extracts are added and things proceed as normal.

I am sending my lovely wife on a reconnaissance mission to my homebrew supply store on Thursday. I should be brewing by Friday.... which reminds me, I am going to recover the yeast from the bottles of beer I will drink tonight and make a yeast starter. No need to buy new yeast. They should multiply and be ready to go by Friday.

Science Camp: Day 1

Well, day one of science camp is done. The camp runs from 12:30PM to 5:30PM for 4 days.

Here is a summary of what went on at Summer Science Camp 2007, Day 1:

All 30 campers showed up. That was nice. They all got outfitted with a binder and name tag. Then we started with a bit of overview and a few ground rules (Safety #1, listen #2). We broke them up into 3 groups of 10. Each group has a counselor.

On day 1 they did chemistry, biology and robots.

In chemistry, I had them synthesize some paint pigments. We made Prussian Blue (KFe[Fe(CN)6]) from iron (III) chloride and potassium ferrocyanide. We made chrome yellow (ZnCrO4) from zinc sulfate and potassium chromate. We also made malachite (CuCO3*Cu(OH)2) from copper (II) sulfate and sodium bicarbonate. During all of the Chemistry we talked about reactions, precipitation, safety, measuring, keeping a lab notebook etc... After they made and filtered the pigments, they mixed them with some white acrylic paint and made a painting.

In biology they did tested for bacteria on their hands before and after washing. Some washed with soap, some without, some with antibacterial soap etc... The results should be in today.

In robots, the built some Lego robots and programmed them to do simple tasks.

The end of the day was spent collecting insects on campus. Each group set off to collect as many insects with as great a diversity as possible.

During snack time, I did a demo. I did the methanol cannon demo. It is simple. Using any plastic jug or bottle, about 5 mL of methanol is added to the bottle. Shake it up and add a match. The combustion is impressive. When you try to do it again, it doesn't work because all of the oxygen in the bottle is gone. This leads into a great discussion of combustion, fuel and oxygen.

As a little twist to the methanol cannons, I added boric acid to the bottle. This results in producing a green flame. I'm not sure exactly why, but it has to do with the formation of methyl borate esters. Regardless of the reason, it burns green. I made a video and when I have time, I will try to post that. Right now I'm busy getting ready for today.

So, day 1 of science camp ended. All the students (who were great BTW) survived and uninjured. That's always nice.

Look for another update tomorrow.

Friday, June 8, 2007

Time. A precious commodity

Have you ever noticed how many times bloggers start a post with something like: "sorry for the lack of posts lately. I've been busy." Isn't that annoying? Well, here's another one.

Sorry for the lack of posts lately. I've been busy.

Seriously, I've been busy. I've been teaching summer school, installing ceramic tile in our shower, preparing for an institutional self-study and preparing for the summer science camp I am hosting next week.

The latter is the most interesting.

Two years ago, I decided to organize and host a summer science camp for Junior high aged kids. With the help of some colleagues, I put together a week of science fun for 7 students. Last year the number jumped to 9. Things went well last year. Word of mouth started. This year we maxed out at 30 with a number on the waiting list.

We start Monday. I look forward to the fun. I have the help of a very competent biology professor to focus on biology and I will focus on the chemistry. A few others will contribute to touch on math, physics and engineering.

This year in the chemistry portion I am going to have them synthesize paint pigments, synthesize aspirin, and do a forensic DNA analysis to solve a crime.

One of the pigments I will have them make is Prussian Blue. It is made from iron (III) chloride and potassium ferrocyanide.

(sorry for the small figure. I don't have time to figure out why it won't get bigger. )
After they make the pigment, we will mix it with some acrylic base and paint with it.

Mixed in with all of the serious stuff there must be some explosions. I have a number of demos planned. These include: hydrogen balloons, methanol cannon (mixed with a little boric acid for a green flame), gummi bears and potassium chlorate, and thermite.

I mentioned thermite a while ago. Well, it's time to go big or go home. I am going to do the largest thermite reaction I have ever done. Fear not, all safety precautions will be duly observed. I will also try to video tape it and upload the video.

It should be a fun week, but I have a lot to prepare.

Friday, June 1, 2007

PEG and me

Poly(ethylene glycol) is an interesting molecule. It is a polymer of ethylene glycol made by the polymerization of ethylene oxide.

Ethylene glycol is a dialcohol:

It is used in antifreeze and it toxic.

Recently it was discovered that a number of toothpastes made in China contained high amounts of diethylene glycol. mmmmmm minty deathpaste. DEG looks like:

When ethylene glycol is polymerized with itself it is know as poly(ethylene glycol) or PEG for short. PEG takes on a lot of different properties. The properties vary based on how big the molecule is. Ψ*Ψ at Carbon-based Curiosities recently posted about poly(ethylene glycol) (PEG) and it use in a hot bath.

I have been exposed to PEG in a number of interesting ways. In every instance it have been useful. I will relate three occurrences.

My Ph.D. work in grad school dealt with the use of carbohydrate-functionalized dendrimers to study protein-carbohydrate interactions. A dendrimer is essentially a spherical polymer. I made dedrimers of different sizes with varying numbers of carbohydrates on the surface to see how they interacted with proteins. The goal was to understand more about how these important signaling processes occur.

OK, long story short time. No need to cover everything and bore you, the kind reader.

My first attempt used a phenyl ring as a linker between the dendrimer and mannose. It look like this:

This molecule shown had a molecular weight of about 28,000, and it had the solubility of brick dust. I needed a functionalized dendrimer that dissolved in water. This one did not. The solution turned out to be PEG. I replaced the phenyl group with a PEG group and voila, it was soluble in water. The structure looked a bit like this:

Granted, it's not really a *poly*ethylene glycol, but it is part of a larger molecule.


Since I had laser eye surgery I have needed to use eye drops to keep my peepers moist. One of my favorite brands is Systane. The active ingredient is polyethylene glycol 400. The 400 means there PEG has an average molecular weight of 400 daltons, which translates to a molecule that contains 9 ethylene glycol molecules.


A while ago my daughter was constipated. The doctor prescribed GlycoLax. GlycoLax is polyethylene glycol 3350. It's average molecular weight is 3350, which means it is made up of about 76 ethylene glycol molecules.

In all of these, the function is the same: hold on to water. This is done through hydrogen bonds between the water and the oxygens on the ethylene glycol molecules. It seems to work quite well.