y - is for yeast
“Your mom busted in and said, what's that noise?
Aw, mom you're just jealous it's the YEAST...”

Now let me tell you why that rhyming couplet doesn’t work, or make any sense. First, yeast  doesn’t rhyme with noise. Second, unless you are singing it in the style of the mega hit from Messrs Horowitz, Rubin and Yauch, you can’t fill in the all important … at the end. Thirdly, yeast doesn’t make noise.


Logic aside, if you don’t immediately play that song at top volume, and start throwing your sh*t around (edit: crying because of lockdown), then we can’t be friends. Props to NZ-based brewery, Yeastie Boys, for making this joke earlier, and also turning it into a successful brand.


Don’t be fooled. Behind all this bluff and bravado is a serious blog/message. Blessage. Blossage? Take my advice and don’t find out the urban dictionary definition of the latter.


That blog can be found here.


Yeast is one of the four essential ingredients you’ll find in your favourite pint. Enshrined in the Reinheitsgebot some time ago, by some people on the other side of the channel. I should know, I wrote that blog.


All you need to know is, without yeast, we wouldn’t have alcohol. Of any sort, not just beer. Try to imagine a world where you didn’t embarrass yourself beyond redemption in front of the parents of your best friend when you were 13. Ruin their carpet and terrorise their cat. Waste their best liquor and eat all of the spices in their spice rack. What kind of world would that be? Asking for a friend.


But you didn’t come here to learn things that you need to know. So here comes the science part:


Yeasts are single-celled fungi. Yeasts require no sunlight, and can respire anaerobically. Under these oxygen-less conditions, they convert certain sugars into carbon dioxide, alcohols and fermentation by-products. Yum!


The two most common types of brewing yeast are Ale yeast and Lager yeast. I’m simplifying a little, but basically they enjoy different temperatures and as such were well suited to the changing seasons in these temperate parts. Before technology defeated the weather, you could brew your ales in the summer and your lagers in the winter. 


With time came more science, and now brewers understand the intricate chemical dance of the yeasts, and can pick and choose the type they want to suit the characteristics of the beer they are producing. Knowing exactly what type of yeast you are using is also helpful in reliably creating the same beer time after time. Many a brewer fears the accidental introduction of the common Brettanomyces strain during fermentation. This is responsible for some truly funky flavours which are most unwelcome (once described as a combination of leather, sweat, and horse blanket). Of course, some brewers love to brew with Brett on purpose. And they are wrong.


While a lot of the credit is often attributed to the hop variety, the spectrum of flavours and scents that the yeast is responsible for is truly mind-boggling. Belgian ale yeasts impart complex, fruity, spicy notes. Bavarian ale yeasts give you the wonderful flavours you’d recognise in a weissbier: spice, clove, vanilla, bubblegum and banana. 


On the other hand, a lot of the beer styles recently popularised by the US craft movement, rely on a yeast which imparts no flavour. This really allows the hop characters to take centre stage. And this American ale yeast is what we use in Stowaway, TightFive and Headliner. Tangent is made with a special French Saison yeast and Caper with a Lager yeast of course.


For balance, here comes the religion bit:


Back in the day, by which I mean in medieval times, brewers believed that their grainy mixtures were turned into beer by magic! Ha, idiots! In fact yeast is alllll around us and you can ferment beer just by leaving it exposed to the elements. Monks are pretty good at it. They probably thought it was done by GOD. A bit like the water/wine thing. There’s probably some kind of conspiracy at the heart of this alcohol-religion connection that Dan Brown needs to investigate.


I think that’s enough, don’t you?

Written by Toby Ejsmond-Frey