Tag Archives: yeast

Homemade stirplate

stirplateI recently made a stirplate (with massive help from my good friend Nate) for yeast propagation using a computer fan, magnets from an old hard drive, an A/C power supply from a cell phone, a combo switch/potentiometer from Radio Shack, bolts and a washer from Home Depot, and a plastic container from Target. The whole thing cost me maybe $8.

The single hardest part of this project was cracking into an old hard drive. This required lots of small screws to be removed, and some serious prying.

Once you get the magnets, you can start to test your wiring. Take the fan, and glue the washer to the fan, and once the glue sets, stick one of the magnets to it. Take the A/C power supply, and cut the power cord so that you have the wall plug and the wire. Strip the wire ends, and do some (careful) testing with the fan to make sure that it spins in the right direction.

Next, put the potentiometer inline, between the fan and the power supply, and get your connections set so that you can adjust the speed of the fan with the potentiometer. This is important so that you don’t throw the stirbar when you start up the stirplate. Once you know where all your wires go, you can start to assemble.

Take your plastic container, and set the fan in it, with your bolts put through the fan. Adjust the height of the fan by using the nuts on the bolts to raise the height of the fan. Ideally, you want the fan right up next to the lid, without actually touching the lid. Give it some space, as the lid will come down with your sample sitting on it. This will take some testing. Fill your planned sample jar (erlenmeyer flask) with as much water as you think you might use, and put it on the lid, and plug in your power. If your fan can spin freely with your flask sitting on top of the lid, you’re all set. Take off the flask and lid, and glue the fan in place. I also glues the bolts at each corner just to minimize movement.

Drill a hole in the side of your container for the power to come in, and drill a hole on the opposite side for your potentiometer. Run your wires in through what will be the back, and put your potentiometer in the front opening. Re-test all your connections to make sure that the fan still spins the way you expect when you turn on the potentiometer, then glue, sauter and glue some more until nothing moves.

Close the lid, put on your flask, and turn it on with a stirbar inside. It should look like this:

Stirplate vortex


Book Review: Brew Like a Monk by Stan Hieronymus

brewlikeamonkI must confess that Belgian beers still make me a little anxious. For a long time, I thought that I didn’t like Belgian beers. Something about them seemed a little strange, and I preferred the tamer ales. Then about a year ago, I had a couple that I really liked. My expectations were now very confused. After years of thinking that I didn’t like Belgian yeasts, maybe there was more to it than that.

When I was given an opportunity to read Brew Like a Monk, I made up my mind to throw myself into it in an effort to try to decipher just what differences there were amongst the Belgian beers, and why I might like some more than others, and what better way than to learn about how they’re made, what makes them different, and what flavors the different styles showcase.

Hieronymus begins with the story of the monastic brewing tradition, correcting some misconceptions about their brewing practices, and providing a timeline of the development of Monastic and Trappist brewing. Hieronymus moves on to cover six trappist breweries, their histories and the beer that they have become known for. Next, Hieronymus moves on to Abbey beers, beers that are not brewed within the walls of the monastery, but are either attempting to mimic that style of beer, or have been contracted by a monastery to brew beer for them.

The next two chapters though, are where I really start to dig in. Just in case you didn’t start to gleam some of this information before, Hieronymus starts to get all technical now about mashing and brewing profiles, breaking down even more recipes in the process. Hieronymus then gets into yeast in a big way, going through various profiles of the two big suppliers in the US, Wyeast and White Labs, providing profile information on their popular strains of Belgian yeast, and even breaking them down by temperature range during fermentation, which I thought was really cool. Hieronymus even goes through and tells you which of the big Belgian Abbey/Trappist breweries have a commercial yeast culture available through one of the vendors cited above.

Next comes one of the more challenging, and yet, most important components of Belgian Trappist/Abbey production, bottle conditioning. I’ve always found the process of bottle conditioning to be a challenging one, but I’ve never pitched fresh yeast at bottling time either, something which all commercial brewers do. There are two main reasons Belgian Trappist/Abbey brewers bottle condition their beer, one is for flavor, and the other is to develop the high volume of carbonation expected in the style, which develops best in champagne type bottles with a cork and cage closure.

The last section of the book focuses on the reader and next steps, one chapter discussing the sub-genres of Belgian Trappist/Abbey beers, in an attempt to further educate the reader if they are looking to brew a specific style, or to judge in a competition. The last chapter focuses on recipes and recipe formulation. As a budding brewer myself, I like the tone that this section sets. Here are some recipes, but we encourage you to take these recipes, and draw inspiration from them, don’t brew them ounce for ounce. This has to be one of the best take-aways of this book, that there is no secret recipe, the way to make a special beer is to take it and make it your own, put yourself in the process, and see what happens.

This was definitely an enlightening book, and even though I’m still on the fence about Belgian Trappist/Abbey beers, I feel much more empowered and educated to move forward in my appreciation of the styles, and also to draw a little inspiration from within, and without the walls of the Abbey.

Using a yeast cake

Edit: I do not advocate this method anymore. I do advocate re-using your yeast, but you should wash it first.

If you brew regularly, and especially if you like to use liquid yeast strains, you might want to consider reusing your yeast. As with everything in homebrewing, there is a long list of do’s and do-not’s, but in general, it’s pretty easy to decide if repitching on yeast will work for you.

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Comparing yeast strains

In an effort to develop some staple recipes, I’ve decided to put a twist on the current batch. Instead of two different batches, I did one huge batch of porter — enough for two carboys.

I split the batch between two carboys, and pitched London Ale III into one batch, and S-05 into the other. Check out the difference. Of course, the English ale yeast was liquid, but it had been in the refrigerator for 10 days.

Homebrewing yeast comparison from Joel Mahaffey on Vimeo.

Pitching the right amount of yeast

I’ve been reading Brewing Classic Styles by Jamil Zainasheff lately, and he offers one piece of advice which I have recently taken to heart, and have found to be extremely helpful. Jamil often repeats that you should pitch the right amount of yeast, and that this quantity is often more than most would expect.

When I began home brewing, I began with all extract kits. For better or worse, these kits only required that you follow the brief instructions enclosed within, and your beer would come out fine. I did this successfully for a long time, and developed the notion that one packet of yeast per batch of beer was the correct amount. This turns out only to be the case in extremely mild, low-gravity beers. For many mid-range beers, the right amount is 2 packets, or vials of liquid yeast. This can be expensive, especially with liquid yeast, which is why making a yeast starter can be so helpful. It only requires a small amount of malt extract, and you can vastly increase the amount of yeast you have available to pitch.

When I first learned about yeast starters, it was my impression that they were only necessary for large, high gravity beers, and I made one for fun, but didn’t realize that it can make the difference between a clean fermentation and a slow, strained fermentation, or even a complete versus incomplete fermentation.

While I haven’t managed to over pitch yeast into a batch yet, I have had some very active and complete fermentation. The last batch I made was using yeast that claimed 73% attenuation, but my actual was well over 80%, which was great.

Yeast are the workers for your finished product. You may feel like you’re doing all the labor, but the real alchemists are the yeast — tiny little creatures who can make the difference in the flavor, aroma, and character of your beer. Respect the yeast, make sure there are plenty of them to do their job, and you’ll be rewarded.