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Foam guide

September 16, 2018 BY One Drink A Day

Many of you guys may already know that I don’t drink a lot of cocktails containing egg whites. However I made a gin sour a few weeks back and was asked by a few people how to create a nice foam layer. So here it is.

Just a quick background information/ the science behind how an egg white foam is made. Basically the foam develops in response to the shaking motion which introduces air into the equation. The egg white has a water loving part and a water repelling part. The physical force of shaking or whisking is what breaks up the tight egg white structure. This gives air an opportunity to come in and cling to the water repelling part of the egg white resulting in foam production. It’s actually a lot more complex than that but that’s the best summary I could come up with.

 

You can think of the foam as a meringue (sugar and egg whites beaten together). So what factors influence the formation of foam?

  1. Sugar or a little acid helps foam production. The sugar and or acid acts to stabilise the foam so it doesn’t separate. As described earlier the air clings onto the water repelling part of the egg whites. When there is no stabiliser present (like a bridge), with time the foam can separate or collapse. Sugar and acid helps to bridge this gap and therefore the foam is less likely to separate.
  2. Dirty equipment stunts foam production. Any presence of fat, water or any other chemicals can distrub foam production.
  3. Using room temperature eggs = easier foam production. Warmer conditions make atoms move faster. Essentially the foam production is getting a head start when using room temperature egg whites….. Although I do get a bit funny with storing eggs at room temp.
  4. Metal is better. Using a metal surface makes foam production easier because it’s easier to clean/microscopic molecules don’t attach as well to metal than say plastic.
  5. Shake hard. If you have a weak shake it can lead to poor foam production becasue there is just not enough force to break up the egg white structure which means poor aeration aka no foam.

 I decided to make a Gin sour following the above rules.

I cleaned my equipment with hot soapy water and dried it thoroughly.

I used a small jar to shake the egg whites with the sugar (for my sugar component I used a butterfly pea flower and elderflower syrup hence the blue colour) . This helps to kickstart the foam process (remember sugar is good for foam production) . Using a small jar means you can exert a lot more force with less effort. You can already see some foam action happening here. Make sure you don’t over shake though. 

Add all your other ingredients to your shaker followed by the egg white+sugar mix.

After you dry shake (without ice) you should end up with something that looks like this. I only required about 30seconds of shaking because I had already started the foam production earlier (egg white and sugar in a jar).

Add some ice (larger the better) and re-shake until chilled. Double strain into a glass over ice.

I garnished with a slice of lotus root preserved in butterfly pea flower tea and elderflower syrup (the syrup which I used as my sugar component) gifted to me by the Wild Hibiscus Flower Co. https://www.wildhibiscus.com/

Hope that was useful and make sure to check my IG post tonight for the making of video!

Gin Sour recipe

  • 15mls butterfly pea and elderflower syrup
  • 30ml blood orange juice
  • 60mls Gin (I used Hendrick’s Gin)
  • Half a passion fruit pulp
  • 1 egg white.

Give this method a go if you are struggling to achieve good foam.

 

 

 

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