Reclaim the yeasts!

When you get down to it, home brewing is not just about making beer in your bathtub or garden shed. It’s about joining a clan of individuals, united by their desire to maintain the thousands year old art of turning water with a bit of grain slush into a potable (and potent) drink. Whether you join the ranks from a desire to save money on commercial beers or with a craftsman push for perfection, it doesn’t matter. You have joined a group who are bonded by the brewers craft and, as it turns out, a common language that appears to have been dreamt up after about 6 too many Scottish Heavy Ales.

What on earth do I mean and what does this have to do with yeast?

The other day was bottling day for my Indian Summer Pale Ale. As many brewers know, much of the quality in flavour comes from the yeast. The higher quality of yeast, the better it ferments out the sugars and the better it tastes. Unfortunately, this comes at a price. My local brews shop sells liquid yeasts at $15 a pop. This can be as much as a third of the cost towards making a beer. To make it a little more profitable, you can actually reclaim the yeast from your last beer to use again.

Now here is where the language of brewing starts to come into its own.

As your brew ferments out, you develop a layer of sludgy material in the bottom of your fermenter called the ‘trub’(see image). This is made up of expired yeast (yeast that has done all of its fermenting work and now has nothing to do), as well as fats and proteins that have settled out of the liquid. It is also referred to as a ‘yeast cake’ (possibly when it is no longer in liquid). No, it’s not like any cake you want to eat, it’s more like the stuff you find in that jar at the back of the fridge that might have had tuna mornay in it about 4 months ago.

My trub (or possibly yeast cake)

At this point, there are a couple of options for reusing the yeast. You can leave it there and pour the next batch of beer straight on top (the act of adding the yeast to beer is called ‘pitching’) or, ‘wash’ your yeast and store it in the fridge to be used again.

Washing yeast sounds about as productive as trying to clean dirt, but this is the terminology brewers use. It basically consists of taking sterilised water and adding it to the yeast cake to get the thick sludge into suspension. Transferring this suspended sludge to a large jar you let the sludge settle a little bit, at which point most of the heavier material will settle to the bottom (this is all the stuff you don’t want in your reclaimed yeast. You can then collect the ‘cleaner’ yeast of the top into sterilised jars and store them in the fridge.

Washed yeast

What do you do with it now? Well, I’ve read a number of different views. Some say you should only keep it for 5 days, others say you can keep it for up to 3 months. I’m going to attempt the later because frankly, I’m not brewing a new batch every few days. When it finally comes time to use it, you create a starter. This is where you add the yeast to warm sterilised water mixed with some sugar that the yeast will use to start multiplying with. If the yeast takes off, you’ve got a usable product for your home brew. If it fails to thrive – bin it.

One day later, I now have trub (that I created from my trub)

So what of rest of the brewing lexicon? We have worts, hops and grist. One indulges in a bit of mashing, sparging and racking. There is the krausen and the trub. We have to pay attention to the gravity, attenuation and our lag phase. Considering the science of brewing is called zymurgy, it’s not surprising that talking to home brewers is like a conversation with a drunk.