Tag Archives: cascade

Proof that Guinness bubbles go the wrong way

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Telegraph: Bubbles in Guinness ‘go down not up’ say scientists

Guinness, in the best Irish tradition, does things differently. The bubbles in a freshly poured pint appear to be cascading down the side of the glass – yet the creamy top which is the drink’s trademark remains.

Members of the Royal Society of Chemistry set out to investigate the puzzle over the course of one lunchtime.

Scientists used a super-fast camera that could zoom in and magnify the bubbles 10 times.

The study showed that the more visible outlying bubbles in a pint of Guinness did move downwards, as a result of circulation flow and drag.

At the centre of the glass, the bubbles were free to rise rapidly, pulling the surrounding liquid with them and setting up a circulating current.

Flowing outwards from the surface, the frothy ”head”, the current hit the glass edge and was pushed down. Bubbles held back by dragging on the side of the glass were caught in the circulation and forced to go with the flow – the wrong way, for a bubble.

(Follow the link for the full article)

I have only one thing to say: Cascade!

Cascade!

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This is a guest post from my good friend Max, half of our “Advisory Panel”.

Recently Al asked me recount an event for the Hop Talk readers that happened when we last got together for our annual Octoberfest. As a parent there are times your child may say or do something that makes your heart just burst with pride. This was one of my moments.

It was early Saturday morning and, as tradition dictates, we were opening our Guinness Stouts (which we have coined our “breakfast beer”) as we stood in the kitchen discussing our plans for the day. As we began to pour, my wife called to my three-year-old son who was playing in another room. “Nicholas! Do you want to see the cascade?” Conversation ceased as the cry of “oh boy the cascade!” coincided with the crashing sound of whatever toy my son had in his hand as it hit the floor. This was closely followed by him appearing in a full-out sprint, rounding the corner and jumping up onto the stool at the breakfast bar to lock eyes on the four simultaneous cascades. I’m not sure whose smile was bigger; his from enjoyment or mine from pride.

(Just in case you’re not familiar with the term “cascade”, here’s an illustration)

http://www.youtube.com/watch?v=-X30NAc8khc