How to Save Money Homebrewing: Yeast

One of the nice things about brewing your own beer is that you have the ability to make really great craft beer in a relatively inexpensive way. In this series I’m going to go through a couple of different ways that you can brew smarter and save quite a bit of money along the way. First up let’s talk about yeast!

Beer these days is becoming ever more complex but fundamentally a lot of beer can be broken down into just a few components: barley, hops, water and yeast. While yeast may be one of the smaller pieces of that puzzle it’s definitely a critical one and one that can often end up costing you quite a bit. So how can we save money on yeast?

Choosing Less Expensive Yeast

This should be pretty obvious but if your choice is between a cheap packet of dry yeast or an expensive pouch of exotic liquid yeast there is going to be a cost difference between the two. While many homebrewers swear by the superiority of liquid yeast the truth is that these days dry yeast is actually pretty good and can result in equally delicious beer. It can be true that not all yeast is available in dry form but if it is you can easily save some money by picking up that version instead of buying a liquid yeast variant.

Pitching on Existing Yeast Cake

So you’ve just wrapped up bottling/kegging your latest beer and you’re about to clean out your fermenter when you begin to wonder if you could just save yourself some time and somehow make use of that sludge sitting at the bottom of your carboy. Well guess what? You can and it couldn’t be more simple! If you happen to be brewing that same day (or within a very short time thereafter) you can simply rack your finished wort right into the same fermenter that your last one came out of. This way instead of pitching new yeast the wort will be consumed by the yeast left over from the previous beer!

Some quick notes on this:

  • If your last beer was a “big” one (high in alcohol) or if it had any dry hops you may want to skip this option.
  • Big beers can stress out the left over yeast which can result in off flavours in your next beer.
  • With dry hops you’ll basically be adding that left over dry hop matter to your next beer which could give a bad taste (think: grassy) to the finished product.
  • You’re going to be hitting your next beer with a pretty big over pitch of yeast. This in itself could mean you’ll have some off flavours but it is also an excellent way to make sure your yeast won’t have any trouble chewing through whatever beer comes next. Some people like using this technique to make a normal beer only to leave the yeast cake behind for a “big” beer next. Think of it like a big 5G yeast starter 🙂

I’ve actually tried this very technique before with great success. Just be prepared for a crazy quick fermentation and try to account for the loss of fermentation space of the existing yeast cake.

Harvesting Yeast

Harvesting yeast is a magical thing. Like pitching onto an existing yeast cake it lets you take one purchase of yeast and multiply it many times over for basically free! But even better you don’t need to brew a new beer on the same day you’re bottling/kegging your last one!

There are a few different techniques to do this and some can get quite advanced (i.e. washing yeast, yeast slants, top cropping, etc.) but I’m going to focus on one of the simple versions of it. You’ll just need some sanitized water and sanitized jars to store the yeast in. Mason jars work very well for this.

Option 1: just pour the yeast cake – the leftover contents in bottom of your fermenter – into the jars and call it a day. This yeast, protein and hop combo is called a “slurry” and can be used just like normal yeast the next time around. Of course doing this technique means you’ll get a lot of things beyond just the yeast in your next beer but it’s quick and super simple. Store the jars in the fridge and be sure to make a starter if they’ve been in there for more than a week or two.

Option 2: this is a bit more involved but results in cleaner yeast. Start by pouring some of the water into the bottom of your fermenter right on top of the left over yeast cake. The goal here is to add just enough water so that you can swirl it around and mix up that yeast cake and get everything back into liquid suspension.

Next you’ll want to pour the contents into the jars. Cover the jars up with a lid so that nothing can get in and let it sit at room temperature for about a half hour. You should start to notice a separation between the trub (sludge looking stuff) at the bottom and the beer at the top. The middle milky bit is all the yeast and that’s what we’re really after. Slowly pour from these jars into new jars but leave behind the stuff at the very bottom. You may need to repeat this step one or two more times.

When you’re done you should have a relatively clear mixture. After leaving it sit for a while in the fridge you’ll see it all collect at the bottom into a nice, clean, white yeast cake. Like option 1 above, store these in the fridge and use them to make a starter if they’ve been in there for a while.

And that’s how you multiply one yeast vial into two extra ones!

Overbuilding Yeast Starter

In my opinion this is probably the best option available but unlike the others it requires a bit more as well.

If you’ve ever built a yeast starter you’ll know that the whole point is to build up and make the yeast you have more active and “ready” to get rolling on your beer. Well the side benefit of this process is that it results in more yeast cells being created as well. Extra yeast means that you might end up with more yeast then you actually need… (see where I’m going with this?).

So one way to save money is to purposely “overbuild” your yeast starter. Instead of making a 1L starter you could make a 2L starter, use 1L in your beer like normal and put the other 2L into some mason jars for use later. This is similar to harvesting yeast but makes sure that you are only saving the best, healthy and most clean yeast possible.

The downsides of this are that you’ll need something like dry malt extract (DME) or extra wort to build up your yeast starter in the first place and you’ll obviously need to start a few days before brew day. But really that’s a small price (literally) to pay in comparison to buying a brand new packet of yeast from the store.

If you have a canner at home you can even draw off some wort from your next brew day and can them in mason jars at shelf stable temperatures for long-term storage. This allows you to skip buying the DME altogether which is another savings. Just be careful that you do this correctly so you don’t end up with botulism!


So there you have it a couple of quick and easy ways to save some money on your next brew day!

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