Our fermentation vessel has been sitting at room temperature (~ 20°C or 68F) for two weeks.
It’s time to move some things around. Or move some liquid into some bottles, to be more precise.
In the bottles, we want some final fermentation to happen. This won’t really add any alcohol, but CO2. Perfect to create a bubbly beer! But there is one problem: all the sugar we put in the wort has been eaten up by the yeast in the fermentor.
So we have to add just enough sugar for the yeasts to convert to CO2 gas, but not too much (we don’t want the bottles to explode). We made up a sugar-water solution by boiling 2 cups (473 mL) and dissolving 4 oz (113 g) of sugar, which we mixed into the fermented almost-beer. We also needed to move the almost-beer into our bottling bucket – carefully, as to not add too much oxygen or contaminants!
Next step was to set up a bottling assembly line. Part one: filling the bottles up, leaving about an inch (2.5 cm) at the top.
Part 2: capping the bottle.
And there we are: a bottle of our very own, home-made beer!
About 40 bottles, actually.
Okay, we’re not quite ready. We need to give the yeast another week or two for the final fermentation. After a quick taste of the almost-beer, I kind of hope those two weeks will change the taste (and the bubbliness), because for now it tasted quite bland.
In addition, our special gravity measurement – which gives an indication of sugar content and can be used to estimate the alcohol content by comparing with the original value – wasn’t very promising. Our beer seems to be less than 3%.
But we’re not giving up hope yet! In two weeks, we’ll see what the final product is. I’ve also read that a few weeks of extra “ripening” can help with the taste as well. And we can always give brewing another go, keeping in mind what we’ve learned so far.
While we’re waiting for the yeast to do its thing, it may be useful to learn about what exactly fermentation is. Fermentation. You’ve heard it before, in the context of beer or kimchi or sourdough bread (or in a biochemistry class). But what does it mean? And why isn’t yogurt alcoholic?
Briefly, fermentation is a biochemical process where tiny organisms break down a complex molecule, such as starches or sugars, into a simpler molecule, an acid or an alcohol, while making some energy. This happens in an anaerobic environment – meaning it does not require oxygen. This contrary to aerobic processes, like what we humans do most of the time when we want to convert sugars into energy.*
Yeasts and bacteria are the two types of organisms that do this sugar breakdown. There are three different types of fermentation, depending on the end product.
In a lot of cooking, we use lactic acid fermentation. In this case, the yeast or bacteria convert starches or sugars into lactic acid. Think kimchi, sauerkraut or pickles, but also yoghurt and sourdough bread.
To make alcohol, however, you want to be aiming for ethyl alcohol fermentation. The sugars get converted into ethanol (the alcohol part) and CO2 (the bubbly part). Bakers yeast is also an ethyl alcohol fermenter: there is no real ethanol left in your final bread, but the CO2 production is what helped your dough to rise.
Finally, there is acetic acid fermentation. In this type of fermentation, sugars from grains or fruit are converted into acids. This is what makes vinegar.
Certain microorganisms are better at certain types of fermentation. That is way it is very crucial that the wort does not get contaminated by outside yeasts or bacteria: you only want the alcohol-making types, not the acid-making types. Unless you want to make a sour, that is.
It is also why, to make a sourdough starter, you just leave some sugars (starches actually to be more precise, in the form of some flower in water) out on the counter. The bacteria and yeasts floating around in the air are the ones you want for lactic acid fermentation – and to start up a sour dough culture.
Controlling the rate of fermentation and end products is a balance between making sure you have the right microorganisms (not all yeasts like being in alcohol – let alone making alcohol), balancing the water and sugars (is there enough food?), controlling the temperature (we prefer certain temperature, so to microorganisms) and waiting the right amount of time. That’s why fermentation is a bit of a science and also a bit of cooking. Though science and cooking are actually very similar to start with.
So to recap, fermentation is a process where yeasts and bacteria convert starches and sugars into alcohol and/or acids, with some by products. And yogurt isn’t alcoholic because the milk-loving bacteria are lactic acid fermenters, not alcohol fermenters.
Beer update: checking in one day later
Disaster has struck. We left the fermenter for one day and came back to this mess:
We had filled up the container too much, so once the yeast started munching away at the sugars, the extra build-up of foam caused the stop to come off. Oh no.
So we needed to clean up. We also siphoned out some of the liquid to avoid this from happening again. Hopefully, we did not expose the beer to external oxygen and yeasts and all during this process…
We put the S-stop back on the fermenter. This ensures that no gasses can come in, while gasses can go out. During fermentation, glucose (which is sugar) gets converted into alcohol and CO2. The latter is a gas and needs to go somewhere, so we let it go out.
This was last Monday. Since then, there seems to have been very little activity in the fermenter. The good news is that everything smells quite nice and beer-ferment-like, not sour, so we will move to STEP 7 sometime in the next few days: bottling!
*I say most of the time because when we get muscle cramps, this is because we’ve been working too hard without providing our cells with enough oxygen to do aerobic respiration (the oxygen-needing-kind). In that case, our cells go into anaerobic respiration, which is very similar to fermentation actually. The result of anaerobic respiration is lactic acid (hey – go back and read about how that’s one type of end product for fermentation!) and some quick energy for your cells to use in the form of ATP. Anaerobic respiration is less efficient than the aerobic kind, but it can get us some quick energy in a pinch.
Source for little factoid is that one episode of the Magic School Bus that I remember where Ms Frizzle was doing a triathlon and her muscles started producing lactic acid so the students – who were obviously in a mini school bus inside Ms Frizzle (where else?) – let out the air of the tires so her muscles would have oxygen.
Last weekend, we started brewing. Not ideas (though we have a ton of those), but beer. As this is a first for me, I decided to document the process so I can learn from the likely many mistakes we’ll very definitely be making. And learning some beer science along the way. There are worse things.
Step 1: The Prep
I cheated a little bit here… My brewing partner-in-crime had done most of the preparation beforehand – like buying the grains and all the kit for home-brewing. We biked out to a home brew shop to get the grain milled and buy the last bits of supply, most notably the yeast.
With our newly ground grain (apparently this is called grist and it smelled deliciously sweet), we biked back home and started cleaning everything. Beer is a product of fermentation: yeasts break down the sugars in the grain and turn them into alcohol. To get good tasting beer, you want to make sure that only the beer-making-yeast is doing the fermenting and that all other types of yeast and bacteria are far, far away from your beer.
Hence, we cleaned and sanitized all the equipment. Thoroughly. And then again.
Step 2: Making the mash
Did you know that beer is basically just fermented grain-tea? Not that different from Kombucha tea actually – just not associated with a current health craze. The first step to making bear is soaking the grist in hot water to extract all the sugars that will be later fermented. This is called mashing.
We set up the boiling pot outside, ready for curious onlookers to wonder what we were cooking up.
We filled the pot with about 30 L (7.3 gal) of water, and heated it up to ~ 75°C (~ 170F). We didn’t want the water to boil, like with green tea, if the water is too hot you get a lot of bitter tastes and we want all the sweet sugars to seep out. In this pot we then dunked a giant teabag filled with the grist (~ 4 kg/ 9.25 lb of the stuff).
After an hour, our tea was ready. A little taste confirmed that it we had made grain tea – more correctly known as wort. A little squeeze of the bag, and out it went. We added a little bit of brown sugar (170 g / 0.375 lb), just to make sure there’d be enough sweet stuff for the yeast to eat. [I initially wrote “yeat to yeat”. Help.]
We then measured the specific gravity of the wort. This would give us an indication of how much sugar (more sugar = higher specific gravity) we were starting out with, important to figure out how alcoholic the end result will be.
We were ready for the next step.
Step 3: Hopping the wort
On paper, beer is quite simple. You have water, grain, yeast and hops. Mix them together in the right way, and you get beer!
The next step in our process was adding the hops – without a bit of a hoppy flavor, no beer! We heated up our water to a boil (> 100°C / 212 F) reused the tea-bag-thing, filled it with our first type of hop (12.5 g / 0.44 oz of Northern Brewer). After 45 minutes of simmering, we added the second type of hop (28 g or 1 oz of Fuggles – who names these things?) and Whirlfloc, which is a tablet containing Irish Moss and Kappa Carrageenan and makes sure your beer doesn’t get too hazy.
15 minutes more of boil and we removed the bag, and got ready for cooling. A quick taste of the liquid proved that it already sort of tastes like beer. There’s some sweetness, some hoppiness, some bitterness but it’s also flat and lukewarm. British Ale much?
Step 4: Cooling
Yeast works best at a certain temperature. Too cold and the metabolism slows down, leading to less efficient sugar-to-alcohol conversion. Too hot and the yeast just sort of dies.
To cool the wort to a yeastly comfortable temperature of 25°C (or 77F), we put an immersion chiller into the pot. An immersion chiller is a coil of copper tubes, through which we ran cold water. It took a while (and I was making bagels in the meantime, to be honest, because brewing is a lot of waiting), but we made it. We then transferred the now cool wort – which needs to have as little contact with air as possible because like the good yeast, the bad stuff also really likes this temperature – to the fermentation container. I can tell you that it already smelled like a brewery in the kitchen – which totally makes sense because we were doing just that: brewing.
Step 5: Adding the yeast
We had already prepped the yeast by adding it to some lukewarm water, now it was ready to be added to the wort. Which we evidently did.
Step 6: Now we wait
We’re trying to keep the fermentation vessel at a constant temperature and keep any extra oxygen out. But other than that, there is nothing to do but wait. Updates will come soon, likely to tell you how it all went wrong. Maybe not.
Disclaimer: as with many things, I have no idea what I’m doing. This is not meant as an extensive guide to home brewing, but just as a general walk-through of my first attempt at brewing.