Foam Physics Prevents Beer Spills

Alban Sauret at Princeton University noticed one day that when people would carry a beer away from a bar it wouldn't spill (provided it wasn't full to the brim. Who knows how he decided to investigate why coffee spills out of his mug, but his latte didn't (provided they were filled to the same level). Maybe, like me, he has a lot of coffee stained shirts and pants.

It turns out the foam dampens the sloshing motion of beer and latte. Since there's no foam on regular coffee, it sloshes much easier.

This study actually has some real world implications. Putting a foam on top of a liquid in a tanker truck, for instance, could make the load more stable.

Isn't science fun?

Learning About Water - Part 2

More from the Brewing Network's Brew Strong show.

Your water pH doesn't matter. It's all about Residual Alkalinity. It drives mash and beer pH. Residual Alkalinity is a "triangle" between your water alkalinity, water hardness and the grain bill's color.

Water profiles are a target, a snapshot in time. If your close on sulfate and chloride, you're okay. But use the residual alkalinity. It's not about the amounts of sulfate and chloride, it's about the ratio.

Add salts to the mash based on the amount of water in the mash tun. Salts will dissolve in the low pH of the mash.

This is the water report here in Paradise:

• Calcium - 83 ppm
• Magnesium - 39 ppm
• Sodium - 41 ppm
• Sulfate - 35 ppm
• Chloride - 81 ppm
• Bicarbonate (CaCO3) 364 ppm

So the RA of the water here is 282, according to the spreadsheet. And I should be brewing a lot of dark dark beers.

They did mention that diluting water with distilled water is okay. However, in the next show (notes to come), I should make sure the calcium is at 50 ppm.

Learning about Water

First, I owe all of you an apology.

I thought I had posts scheduled through this weekend.  Apparently, I didn't.

I try to post consistently for the 6 of you that read this, so I try to plan ahead in case things get busy at work or at home. I failed in that planning, and I'm sorry.

Having said that, I do have a few posts to load up on here, so let's get to it.

The best way to learn something is the have to teach it to someone. So any time I try to learn something new, I pretend I am teaching someone. Today, that's the six of you that read this. Congrats!

I bought Water: A Comprehensive Guide for Brewers, a few months ago and tried to read it.

I'm in my 50s, and it's been since the early 1980s that I've stepped into a chemistry class. So about three chapters in I hit the wall. I know that knowing about water will help my brewing, but c'mon! Learning at this age?

Whenever I need advice on brewing I turn to the Brewing Network. So, with the help of a BNArmy buddy, I downloaded the Brew Strong water shows, and got a chance on Sunday (duped into a non-brew day by a pessimistic weatherman) to listen to the first couple of shows. Here are my notes for Show I, expanded slightly.

Water is important to beer flavor, but the most important things in water to brewing are the minerals. Look at it this way: If you use distilled water to make a soup, it will turn out good, but flat. If you add spices and salts to your water, it will turn out much better. Distilled water brings, as Alton Brown says, nothing to the party. (He also has a fun podcast.)

Water pH plays a role. Acidic water (under 7 pH) makes a drier beer. Basic water (above 7 pH) makes a maltier beer.

Calcium is important for yeast health, mash pH, and beer clarity. It should be 50-100 ppm.

Magnesium is good for yeast health, but the yeast will get what it needs from the mash. Too much can give you the shits. It's used in Milk of Magnesia.

Chloride is a malt enhancer, and sulfate enhances hop flavor. The key is to get a good balance between the two. The bicarbonate concentration of you water lets you know what you can brew.

• 0-50 ppm: pale beers
• 50-150 ppm: orange to brown beers
• 105- 250 ppm: dark beers

The ratio of Chloride to Sulfate lets you know how bitter or malty your beer will be.

• 0:.5 - Very bitter
• .5:.75 - moderately bitter
• .75-1.25 - Balanced
• 1.25:1.50 - Malty
• 1.5:2 - very malty

This is where the first show ended. 

Let me know if I got this right. I want to make better beer, and water is a part of it.

Why Bubbles Fall in Guinness

Sometimes, scientists should probably not spend too much time contemplating the beer they are drinking.

A group of Irish mathematicians attempted to explain why bubbles in a pint of Guinness (naturally) fall when bubbles in a pint of lager, say, rise.

After hours of complicated math, they determined that it depends on the shape of the glass. When poured down the center of a cylindrical glass all the bubbles will rise together. But when poured down the center of a regular shaker pint glass or the ubiquitous Guinness tulip glass, the bubbles in the center rise to the top, causing a pressure imbalance which pulls the bubbles on the sides of the glass down to the bottom of glass and into the column of rising bubbles.

I think that's how it works. Maybe you could get a clearer explanation here or here.