Before I was a professional brewer and just putzing around at home with my brewing, I would have some brews that went really well; and then I'd have others that went...not so well.
And it was always a bummer when all the effort, time, and money I put into a batch turned in
to a less-than-stellar drinking experience. But then I started brewing beer for a regional
brewery, and I learned more and more about proper yeast management. That's when I learned that yeast starters could make my brews at home consistently better, and I've rarely made a beer since without one. There are several different methods I've seen, and used, for making yeast starters; and I've seen people both online and in person swear by single methods to do things. But I am someone who likes to have a quiver of methods that will work in different situations. My brewing process can flow better with easier tactics, or I can make up for non-ideal conditions with a bigger effort. And I'd like to share my experiences of those with you; but first...what is a yeast starter, and why or when do we need one to make good beer?
A yeast starter is basically a small-scale fermentation that is a prelude to your planned larger batch of beer. This is a tactic used to grow and fortify the yeast you are going to use. If you feel like your yeast is a bit older or just not enough, you will want to do a starter. For example, if I were to make a 5-gallon (21L) batch of beer and felt my yeast may be a bit sluggish or low in numbers, I would do a 0.5-gallon or 2L starter a day or two ahead of making the larger batch. And for any starter I do, regardless of method, it starts with the same formula:
Make a 1.038 gravity wort with the size of starter you want. I typically will do 100g of dry malt extract (DME) into 1L of water to achieve this. You can scale it however you need. 50g into 500mL or 200g into 2L, it will work out to the appropriate strength.
Boil the wort for a few minutes (5-10) and chill it as quickly as possible. Ice baths or set and forget are just fine.
Put your wort into the propagation vessel of choice for whatever method you're utilizing.
Pitch the yeast (one method requires some small wort prep first) into that wort and let it go to town.
And there are two methods at my disposal that I like to incorporate into my own beer making. One is the traditional Erlenmeyer flask on a stir plate, and the other is the "shaken-not-stirred" (SNS) method, created and made popular by Mark Van Ditta and Denny Conn. Both have their merits, but I use them at different times for different goals. There have been threads I've seen on homebrewing sites and blogs where brewers claim that they've "lost" or given away their stir plates because the SNS is the only way to go. And while I do like and admire that brewers are developing ways to make their brewing simpler and more accesible, I'm certainly not misplacing my stir plate anytime soon.
This is my (poorly) homemade stir plate from a cigar box, computer fan, rheostat, magnet, and an Amazon special "On/Off" toggle switch. There are many like it, but this one is mine. All said and done, I believe this cost me less than 15usd. Times, of course, have changed since then; but I would be surprised if it cost more than $30 at the time of this post.
However, if you don't have the gumption of producing the equivalent of this blundering brickhouse; a "cheap" one like this will do you just fine. I obviously have not used it, but the reviews on it look solid. Other stir plates look to be in the 100-150usd range, and I just find that a bit ridiculous. "Buy it for life," I suppose...but I think the $40 one will last too for our particular use.
To use a stir plate, you will want a vessel that is easy to clean, durable, and heat resistant. There is no better option than an Erlenmeyer flask for this task. I have a 2L one that works well for most of my batch sizes and styles, but I do have a larger one for when I need really big yeast counts as you can only get a certain amount of yeast to fit in a certain volume. A magnetic stir bar will be put inside of the flask, along with the wort/yeast combo, and allowed to sit with the spinning stir bar creating a vortex. The vortex is crucial for optimum yeast growth as it provides a greater amount of gas exchange for oxygen, which the yeast need for reproduction. Keeping the velocity of the
stirrer low is crucial as well, so don't overfill your flask! I won't go too in depth on Crabtree effect and all that here, but I will say that the stirring method is better for me when I need more yeast/volume of starter wort. Doing this process right will yield, in my experience, very good and reliable growth; and I can do it in steps when I really need that initial growth in the case of older yeast or propping up a slant. So this is why I will use a stir plate and have not fully transitioned to the SNS method. The downsides to a yeast starter on a stir plate are that it is trickier to get timing right for brewing/pitching (too long on the stir plate can lead to a gross-smelling concoction along with poorer yeast performance), it can take a bit more malt extract to do vs the other option, and the equipment is not free (unless you luck out on a giveaway or somehow acquire one in ways that are less-than-savory).
Alright, now on to the "shaken-not-stirred" method. You need almost no equipment, it is a very simple process (meaning no fuss), and it does do a good job of propagating yeast. My only issue with it is that I find that I may need more yeast than the SNS can provide with a smaller amount of wort. The stir plate opens up more options with a larger flask, and I don't need to shake 2L or 3L of wort in a 12L bottle until my arms feel like revolting against me. But when I only need a small boost with my yeast I will follow the initial methods outlined at the top of this post to make a starter wort of 500mL, and I will then pitch the wort into a clean and sanitized growler. My growler is only a 2L volume, where the true method instructions mention to use a 4L vessel with 1L of starter wort, so that may be my issue I've been seeing with yeast count discrepencies. In any case once the boiled, chilled wort is in the clean, sanitary vessel, BEFORE pitching the yeast, shake that thing like it owes you money until there is a lot of foam...more foam than liquid. This helps the surface area for oxygen exchange and increased yeast growth. Pitch the yeast once the starter is adequately aerated, and let it go for 18-24hrs or until you see it is at "high krausen."
Then pitch the entire contents of your propagator into your batch of beer and watch it take off. It's as easy as that. I do love this method because it does a great job of increasing yeast numbers and driving vitality without all of the equipment. It helps to lower the barrier to entry of brewing great beer even more; and hats off to Mr. Van Ditta for coming up with such an easy, cheap, and effective method for taking care of our yeast friends.
Happy brewing!
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