When we left off, we were talking about sex and alcohol.
Ok, so maybe it’s more reproduction than sex. And alcohol will definitely come into play but not in the usual way.
In part one, we mentioned the old saying “brewers make wort, but yeast makes beer”. We’ll need to grow lots of our little yeast friends to do their part – they have a much harder job than cooking wort. They reproduce asexually, i.e. they bud off daughter cells with no need for male and female hanky-panky. But we can get them to reproduce more efficiently if the conditions are right.
So what do we need to get them in the mood? Barry White singing in the background? Ravel’s Bolero to build them up into a crescendo? No, our aphrodisiac is oxygen. That makes it easier to grow our budding brewers – it makes their cell walls more permeable to nutrients.
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At the end of the brewing day in part two, I transferred the cooled wort to a fermentation bucket. Because I wanted to introduce lots of oxygen into the wort, I poured it into the bucket with a good amount of splashing and did the same with the top off water. Then I whisked it for another minute to aerate it even more. Note that this aeration should be done after the wort has been cooled.
Once I aerated the wort I “pitched the yeast” that I started the day before into the fermenter, sealed it off, and waited for the fermentation process to do its thing.
Ok, I lied. Before pitching the yeast, I took an Original Gravity (OG) reading with a hydrometer to measure the density of the wort. But to understand why, I should describe the three phases of fermentation.
- When we first pitch the yeast, it goes through a “lag” or “adaptation” phase. During this time, they scope out the neighborhood, find out what resources are available, and use them to turn themselves into reproduction factories. Oxygen is a key resource here; while they can reproduce without it, they do much better with it. This phase usually takes between 8-20 hours for ales. Oh, and that yeast solution I started the day before? It’s just a miniature batch of wort and yeast, taken into the lag phase to make more yeast.
- Once the oxygen runs out, rather than using the malt sugars and oxygen to reproduce the yeast just eats the sugars and releases a few other items. The two most interesting are alcohol and carbon dioxide. This “primary” or “attenuation” phase can be very vigorous; if you look through the sides of the fermenter it almost looks like it’s boiling. During this time the gravity of the wort drops – as much as 3/4 of the density provided by the malt disappears as the sugars are replaced by alcohol and the carbon dioxide bubbles off. A foam called “krausen” forms on top of the wort. This phase usually takes 2-6 days for ales.
- Once the sugars get low and this yeasty version of a bacchanalia winds down, a “secondary” or “conditioning” phase begins. A lot of the yeast goes dormant or dies, but some stick around to munch on less digestible sugars and other chemical byproducts from the primary phase. This generally improves the flavor, but can add negative flavors as well. If you were not careful with your sanitation you might not like the results. Yeast and other sediments will also settle out during this time – how much depends on the type of yeast. Conditioning can take as little as a couple weeks, but can continue for months, including time in a bottle. (Cue Jim Croce).
Back to “Why Original Gravity”. There are a couple reasons for this. First, if you measure the gravity after primary fermentation is done to get Final Gravity (FG), you can use the difference between OG and FG to figure out the alcohol content. Second, if you’re not getting a very active primary and are wondering if your yeast wasn’t up to the task, checking the gravity will let you know for sure.
After the primary fermentation winds down, I’ll usually transfer the beer to a secondary fermenter. I’ll do this to help get the beer off of all the sludge. (Or “trub”. Beer geeks seem to have a special word for everything). Trub is residue from crushed grain, hops, and yeast. This is a controversial step; many in the brewing community suggest the risks of introducing contamination and oxygen during the transfer outweigh the benefits. For ales they’re probably right, the sludge doesn’t really get funky until after three weeks or so, and by that time you can bottle. But I learned to brew doing the transfer, and especially since I started doing partial mash I have a lot of trub.
Wait, didn’t I highlight the benefits of oxygen early on? Why is it bad to add it now?
It seems once primary fermentation begins, introducing oxygen can cause the beer to become stale more quickly and we don’t want that. So any transfers after that point need to be made slowly and carefully.
We use a siphon, aka “racking cane” to do the transfer. (Where do they come up with these names?)
I’ll leave the beer in secondary for a couple weeks of conditioning, and then I’ll bottle. But is it ready to drink? Not really.
There’s a small matter of carbonation. Do you like flat beer? The more hardcore will set up a system with a small refrigerator, a keg, and a carbon dioxide tank. That saves them the trouble of bottling, and they can carbonate from the tank. It’s plausible to fill bottles or growlers from that.
But for those of us stuck with bottling, there are a few more steps.
- I’ll take another Final Gravity reading and taste the beer. It’s not ready, but I can see how the flavor is coming along.
- Acquire bottles. You can buy them, or just reuse commercial beer bottles – but no screw tops. Once you’ve got them you can reuse them indefinitely.
- Clean them well. The first time can be a hassle if they’re reused bottles that have been sitting around growing crud. You’ll quickly learn to give your bottles a thorough rinse after you drink a home brew – it makes cleaning them much easier the next time around.
- Prime the beer for carbonation. Since we don’t have our CO2 in a tank, we need to grow some. Remember what happened in primary fermentation? The yeast ate sugar and released alcohol and carbon dioxide. So, we’ll give it some more sugar to eat. To do this, boil up some water to sanitize it, mix in a half cup of table sugar, let it cool a bit and put it in the bottom of that bucket we used for primary fermentation. Then, rack (siphon) the beer from the secondary fermenter (carboy in this case) slowly into the bottling bucket. Give it a gentle stir when finished so we get an even distribution of table sugar, but not enough to introduce oxygen.
- Time for an assembly line.
- Sanitize the bottle with Star San
- Run a hose from the spigot of the bucket to a bottling wand. That’s a little tube with a pin valve on the end – push the pin against the bottom of a bottle, the valve opens, and beer flows. Lift it up and it stops.
- Fill the bottle
- Cap it and crimp it down
- Set aside for storage at room temperature. We’re still fermenting and we want our yeast in their happy zone.
Even with all the settling there’s still going to be yeast in the bottles with the new sugar. This time, when they eat the sugar and release carbon dioxide, it’s sealed in the bottle and the gas is absorbed by the beer – ergo carbonation. This process takes about two weeks.
Finally, it’s time to cool a bottle and have a taste. Depending on the type of beer, it might be great already, or need some more aging time in the bottle to really achieve peak flavor. But hey, who drinks 5 gallons of beer in a hurry? Might as well start early, and see how it develops over time.
Yeah, I know, even those who’ve managed to read this entire series are saying, “That’s too much work, I’ll just run down to the store and buy a six-pack, or down to the bar.” And I won’t lie, if you add up all the time spent on all the steps over the five weeks or so it takes to make a batch it’s probably an 8 hour day. But it’s a hobby. How long does it take to go camping, or fishing, or knit a sweater? How much time and money would you spend on golf clubs and green fees?
You might also be saying, “that’s too complicated, I’ll never get it right.” I can see how you might get that idea after one read through, but with a little study the pieces fall into place. Before I brewed my first batch I built myself a spreadsheet/checklist to ensure I didn’t forget anything, but by the time I did the batch I didn’t really need it. Just the process of working up the steps from my reading gave me a comfort zone. After doing a few batches it’s no more complicated than cooking up any other dish you’ve made a few times.
Although I touched most of the bases for making a good ale, should you wish to continue your brewing education, here’s some ideas:
- Check if your town has a home brew supply store. It’s a good bet they offer classes too. A basic brewing class will take 2-3 hours and reinforce my talking points.
- There may be a “You Brew” style establishment in your area. These places provide the equipment, the ingredients, recipes, and hand holding. You may not learn brewing in depth, but you’ll get a feel for the process and end up with beer similar to what you could brew at home.
- Are you good at self-study? There are many books, magazines, and web sites to read. I started with “How To Brew” by John Palmer. This is a free book presented in web format. John Palmer is one of the leading voices in home brewing.
- Maybe you’re more visual. You can find You Tube videos on almost any aspect of home brewing. If you’re looking for something more integrated, you might look into Homebrew Academy. The basic site is just a beer blog, but there are video based classes available for a fee.
So that’s the scoop on making beer. Congratulations for making it all the way through. Feel free to award yourself a craft beer. 🙂