Gowanus Brewery

Using the New Stir Plate by Jeremy
May 31, 2008, 12:00 am
Filed under: equipment, yeast

The stir plate worked, but I need to fine-tune how I use it.

It lacks the power of a commercial stir plate, so I can’t get a vigorous stir when the 500 and 1000 mL flasks are full. That reduces the amount of oxygen I can pull from the air in the flask to the wort. It has more than enough power, though, to keep the yeast suspended and the wort well-mixed after that. Still, in the future, I’ll shoot to fill these things to only 3/4 capacity.

To begin, I stirred the wort at full speed before and after pitching the yeast to maximize the oxygen exchange. Once fermentation became noticeable, I stirred the starters only once a day to keep the beer evenly mixed. I noticed that, at least for the 1000 mL starter, which I let ferment out over about 3 days, that foaming would subside in between mixings and restart afterwards. That makes me think it was helpful to some extent, but not more than a vigorous shaking would be.

I have to do some follow-up homework here because at this point I don’t see how this setup is more beneficial than shaking the starter by hand vigorously before and after pitching the yeast and then once a day afterwards. The only thing I can do with the stir plate that I can’t do by hand is to leave it on throughout fermentation, which I didn’t experiment with.

Anybody have any information on this?

DIY Stir Plate by Jeremy
May 20, 2008, 12:00 am
Filed under: equipment, yeast

I mocked up a homemade stir plate last night to prepare the Gowanus Strong Wheat yeast starter.

There are already several how-to’s online with in-depth build documentation, so I’ll just give you the short version here. There are four primary components that go into this project:

Enclosure: This I picked up from Radio Shack.
Computer Case Fan: I have several of these on hand.
Rare Earth Magnet: Harddisks contain two powerful, semi-circle magnets each.
12 volt AC-DC Power Supply: I used an old 12-volt, 500 mA router wall wort.

Plus, of course, various other hardware, including power connector, potentiometer, switch, wiring, etc.

The very last thing to get squared away is the stir bar. At the moment, I’m using a short piece of paper clip, but I’m trying to get my hands on some reasonably-priced magnetic stir bars. As obvious as it may be, this is a worthwhile upgrade. Unfortunately, I probably won’t get one until after the Gowanus Strong Wheat is finished.

Yeast Math by Jeremy
May 1, 2008, 12:00 am
Filed under: yeast

I’m trying to finish our Yeast Starter Method page, so I’m reviewing the various methods used to estimate how many yeast cells there are per unit volume yeast slurry and what volume yeast slurry you need for a given batch of beer and, oye, my head’s already spinning…

Obviously, there are simple rules you can memorize to avoid the headache of recreating the underlying calculations, but it seems worthwhile to go through the exercise at least once. I’m not sure how to organize this information, so I’m just laying out the most important relevant principles here:

Maximum yeast cell densities are not achieved until between 24 and 36 hours after pitching.

Cultures should be used immediately, or refrigerated for up to 1 week before using.

There are about 4.5 billion yeast cells in 1 milliliter of yeast solids (solids with no excess liquid).

Harvested slurry is typically in the 40% to 60% solids range.

For ales with a starting specific gravity below 1.060, pitch 6.0 million cells per milliliter wort. For starting gravities between 1.061 and 1.076, pitch 12.0 million cells per milliliter wort. For starting gravities greater than 1.077, pitch 18.0 million.

Pitch rates when using harvested slurry should be 1.5-2 times the rate of laboratory grade culture.

Most of this information comes from the Wyeast Home Brewing Technical Information Page.

Raspberry Wheat – Bottled and Labeled by Jeremy
April 22, 2008, 12:00 am
Filed under: all-grain, beer, label, raspberry wheat, yeast

Whipped up this label a few minutes ago and finished bottling the Raspberry Wheat Ale before that.

I haven’t had the free time lately to put more creative energy into my labels, which is why the last few have been so similar: background picture + cool font. It’s boring, but it’s the beer that’s important right!

Anyway, I tasted the raspberry wheat again while bottling and it still tastes very good. Any concern I had over using too few raspberries went out the window tonight. Overall, the beer is dry, light-bodied, and the raspberry flavors stand out pretty well. I think the primary reason halving the amount of raspberries you would typically add worked out so well is that I used an American wheat yeast, which ferments dry and clean. German wheat yeast produces rich flavors like bananas and cloves and would compete with the berries. Of course, I’m still curious how this beer would have tasted with five, or even ten, pounds of raspberries…

Raspberry Wheat Progress by Jeremy
April 8, 2008, 12:00 am
Filed under: beer, raspberry wheat, yeast

The Raspberry Wheat Beer has been busy.

The raspberry sugars triggered a nice second round of fermentation that hasn’t quit after three days. This picture is was taken about 12 hours after adding the raspberries, even if it’s not clear, the beer was already looking bright red. Also, the new fermentation is producing a clean, full, white foam at the top of the carboy, just what I’m going for in the end product.

So, everything is on track and looking good. The only thing left to do to close the book on this recipe, besides entering it in a comp somewhere, is to get my hands on some yellow raspberries. They’ll add a great twist with a slightly different raspberry flavor and intense bright yellow color. I can’t find these for sale retail, so I’m ordering plants to grow them myself. They are early fruiting, but still I don’t think I’ll get a harvest until mid to late summer.

Yeast Starter Worked Out Well by Jeremy
April 7, 2008, 12:00 am
Filed under: raspberry wheat, yeast

Fermentation for the Gowanus Raspberry Wheat Ale was healthy and more complete than the last batch.

The final gravity was 1.014, an improvement over the previous batch, which stopped at 1.016. I don’t have any concerns or complaints about it. It just worked.

Since I added raspberries to this beer in secondary and they are a potential source of contamination, I decided to sample and save yeast from primary, instead of secondary, like I did last time. The drawback is that the yeast sample contains wheat, barley, and hop sediment, in addition to the yeast. In all likelihood, contamination won’t be a problem, so I may take another sample at the end from secondary and use that for future batches.

First Yeast Starter Pitched by Jeremy
April 2, 2008, 12:00 am
Filed under: yeast

My yeast starter looks great. Good volume. Great color. And, hopefully, tons of healthy yeast.

I grew this yeast up from a 6-ounce starter last week in about a quart of a simple wort. That lag between making the starter and pitching it will be something I look at if I don’t reach a better final gravity, but as of yesterday fermentation appears active and healthy. The only potential issue I see so far with this experiment is that I foolishly pitched my entire supply of this strain of yeast. In the future, I will keep at least one sample set aside in case my batch of beer goes south.

Actually, I’m not too worried about that. Barry and I were talking about it last night: out of the 10 or 15 batches we’ve done since the end of last summer, we haven’t lost a single batch of beer to contamination.

Are we lucky or just plain good?