As a proud owner of a Jewish mother, a Jewish Grandmother, and now a little baby, I am quite accustom to gushing. It usually starts off lightly and then bursts into a full force stream of compliments about how cute/smart/funny/alert/strong/perfect the baby is, and how she looks like me (ok, so they're not all compliments... ) And that's great when it comes to my kid. But when it comes to my beer I prefer it to, well, stay in the bottle.
Case in point: I have a few bottles of beer that I brewed with a fellow homebrewer (Let's call him "P.I.C." for "Partner in crime") back in November. It was a Belgian Triple that was brewed on PIC's system, bottled by him (without me present), and was lagered in his fridge for a month before it was delivered into my waiting hands sometimes in early December. I got thirty bottles that promptly went into the basement of my building, where the temperature at this time of year is around 12 degrees C. So far so good.
I drank a couple of bottles, and they were good, but they could be better. A bit of research taught me that a Tripple should be aged for a couple of months to achieve peek flavor, and so I left them in the dark, cold basement to age slowly, and for the past month I've been slowly going through them.
But it turns out that I'm not the only thing going through them. It was slow at first: a feeling that the beer is a touch over carbonated. Then a foam that rose out the bottle when I first opened it. Then it got to the point where I'd have to have a glass ready to pour the beer into as soon as it was opened. And finally, a couple of days ago, I opened one of the bottles (very slowly, after cracking the cap open a couple of times to let the gas escape) and was treated to a full-force geyser out of the bottle. No doubt, it had a gushing problem.
Why do bottles gush? Well, in the simplest terms, it's when there's too much pressure in the bottle. Since pressure is the result of fermentation, over-pressure is, loosely speaking, the result of over-fermentation. That is, there was more fermentable material in the bottled beer than was required to carbonate it. There are three main reasons for this:
1. The beer didn't finish fermenting before it was bottled, leading to residual sugars being fermented.
2. Too much priming sugar was added
3. The beer was infected with a bacteria or foreign wild yeast that can ferment sugars that ordinary beer yeast cannot.
The first case happens sometimes when cold-crashed beer gets warm again. The yeast wakes up, eats up the rest of the sugar, and presto! Gushing. If there's enough sugar, the bottles wont just gush, they'll explode.
The second case is self-explanatory. If you dump too much sugar in the beer before you bottle, you'll end up with too much bottled gas. This happens a lot with beer made from kits. Beginner brewers just dump all the sugar in without calculating what they actually need, and without realizing that often a kit comes with two or even three times as much sugar as necessary.
The third case is typically the result of poor sanitation somewhere a long the process. Typically, if the gushing is not limited to a bottle or two, but is consistent throughout a batch, the problem is in the bottling equipment, the racking equipment, or the fermenter. In other words, something that comes in contact with the entire volume of beer.
So what happened to the Tripple? Well, it's a bit of a mystery. On the one hand, PIC insists that his bottles didn't gush. On the other hand, he tends to drink his beer so green it's practically still wort. On the third hand, I know the guy, and he tends to pour priming sugar in by the cup-load. On the fourth hand, the slow progression of the process seems to indicate infection. On the fifth hand, this is not the only beer he had bottled that I've ended up wearing rather than drinking, so that points to something in his process. And on the sixth hand, he claims it's all my imagination, and that it never happens to him.
I don't know what happened to the Belgian. To be safe, though, the next time I open a bottle, I'll do it in the tub. And take a video, just to prove I'm not imagining things...
Showing posts with label cold crash. Show all posts
Showing posts with label cold crash. Show all posts
Tuesday, February 21, 2012
Monday, January 30, 2012
Suicide bombers
Today, ladies and gentlemen, I want to write about an issue that has recently hit very close to home in my part of the world: Suicide bottles, a.k.a. Bottle bombs.
We all know that feeling of coming home in the evening and smelling that intoxicating aroma of beer merrily fermenting somewhere about the house. It's a great smell, full of promise and future, and is a fantastic thing to come home to, as I did a couple of nights ago. I stepped into my living room to the smell of fermentation and thought "wow, this IPA in the fridge is going to be great". It was late at night, and I was carrying the miniature brewmisstress in my arms, so I went to sleep and thought nothing of it.
The following morning, yesterday, I woke up with a nagging feeling. I couldn't quite place it. I went through my morning routine and got ready to leave the house when it suddenly hit me: The IPA was done fermenting three days ago! It shouldn't smell like this! I should check on the beer! So I went to the fermentation fridge, and opened the door...
*Crunch...* The sound of grating glass as the fridge door opened to reveal the devastation inside. It Seemed that my entire stock of cider (8 bottles) had decided to commit seppuku together, and take my fridge with it. Well they failed on the last part, as the fridge still worked, but it was coated, and I mean COATED with a fine coat of glass shards stuck onto every available surface with sticky, sticky dried cider. Add to this the dried remains of the latest yeast irruption from the fermentor, and you can only guess at what my fridge looked (and smelled like). It was incredible. And extremely messy.
I wont bore you with the details of the cleanup except to say that it took blood, sweat, and tears (the baby was crying) to clean it up. Not to mention a whole roll of paper towels, some rags that may never be used again, and lots of vinegar water. At the end, though, the fridge was back to it's usual sparkly-clean self (um, yeah, usual) and the beer that survived the explosions wiped down and placed back. I even found some odd bottles I forgot I had.
Of course, this is all my fault. Back when I made the cider I had made it with rather too high a starting gravity (1.079), and in order to avoid having 10% cider I cold crashed it when it still had a good amount of sugar in it. It's been sitting at temps that have been getting slowly higher with the last couple of brews, and finally, with the IPA fermenting at a whopping 20C it could take no more. The yeast had woken up with the heat, found sugar, and got to eating. And the rest is very messy history.. :)
So what have we learned? (I should say, re-learned. I should already know these things..)
- That bottle bombs are real. They are not a myth, and they have quite a spectacular force.
- That when you store beer, you have to be mindful of the temperature it will hit in storage. This is why is a good idea to let the beer carbonate at a rather a ambient temp, btw.
- That cold crashing really doesn't kill the yeast. They're hardy little tikes, and they loooove their sugar.
Luckily there were no casualties other than the cider, which no one was drinking. It was also stored in useless green and clear bottles, so no loss there. I already bought a new can of apple concentrate, and am planning to make cinnamon-spiced cyser when I get the chance. I think this time, I'll aim at OG of 1.055..
We all know that feeling of coming home in the evening and smelling that intoxicating aroma of beer merrily fermenting somewhere about the house. It's a great smell, full of promise and future, and is a fantastic thing to come home to, as I did a couple of nights ago. I stepped into my living room to the smell of fermentation and thought "wow, this IPA in the fridge is going to be great". It was late at night, and I was carrying the miniature brewmisstress in my arms, so I went to sleep and thought nothing of it.
The following morning, yesterday, I woke up with a nagging feeling. I couldn't quite place it. I went through my morning routine and got ready to leave the house when it suddenly hit me: The IPA was done fermenting three days ago! It shouldn't smell like this! I should check on the beer! So I went to the fermentation fridge, and opened the door...
*Crunch...* The sound of grating glass as the fridge door opened to reveal the devastation inside. It Seemed that my entire stock of cider (8 bottles) had decided to commit seppuku together, and take my fridge with it. Well they failed on the last part, as the fridge still worked, but it was coated, and I mean COATED with a fine coat of glass shards stuck onto every available surface with sticky, sticky dried cider. Add to this the dried remains of the latest yeast irruption from the fermentor, and you can only guess at what my fridge looked (and smelled like). It was incredible. And extremely messy.
I wont bore you with the details of the cleanup except to say that it took blood, sweat, and tears (the baby was crying) to clean it up. Not to mention a whole roll of paper towels, some rags that may never be used again, and lots of vinegar water. At the end, though, the fridge was back to it's usual sparkly-clean self (um, yeah, usual) and the beer that survived the explosions wiped down and placed back. I even found some odd bottles I forgot I had.
Of course, this is all my fault. Back when I made the cider I had made it with rather too high a starting gravity (1.079), and in order to avoid having 10% cider I cold crashed it when it still had a good amount of sugar in it. It's been sitting at temps that have been getting slowly higher with the last couple of brews, and finally, with the IPA fermenting at a whopping 20C it could take no more. The yeast had woken up with the heat, found sugar, and got to eating. And the rest is very messy history.. :)
So what have we learned? (I should say, re-learned. I should already know these things..)
- That bottle bombs are real. They are not a myth, and they have quite a spectacular force.
- That when you store beer, you have to be mindful of the temperature it will hit in storage. This is why is a good idea to let the beer carbonate at a rather a ambient temp, btw.
- That cold crashing really doesn't kill the yeast. They're hardy little tikes, and they loooove their sugar.
Luckily there were no casualties other than the cider, which no one was drinking. It was also stored in useless green and clear bottles, so no loss there. I already bought a new can of apple concentrate, and am planning to make cinnamon-spiced cyser when I get the chance. I think this time, I'll aim at OG of 1.055..
Monday, January 9, 2012
Cold Crashing
As home-brewers we do not, as a rule, filter our beers. And so it becomes an article of pride for many of us to have beer that is unfiltered, and yet crystal clear. We like the yeast, we use it to turn our wort into beer, and then we would like it to sink down as quickly as possible and leave our beer clear and transparent.
One of the methods that we use to achieve this lofty goal is Cold Crashing.Cold crashing is a process by which we take the beer once it's done fermenting, and abruptly drop the temperature in the fermentor from the blissful 17-21C of ale fermentation to a blistering 4C for about two days. (Lager, being laggered at 4C anyway is not cold crashed. Or if you will, Cold crash is part of its basic process.) The idea is that the yeast will become dormant and flocculate out of the beer, leaving it clear. A secondary use of cold crashing is to stop fermentation before it is complete, in order to leave more sugar in the beer and a lower alcohol content. (This is kind of a misconception, since you don't stop fermentation, you suspend it, and the yeast will take it back up if you raise the temperature again)
Personally, I can never bring myself to cold crash a beer, and instead I prefer a slower process in which I drop the temperature by about 1 degree C every 12 hours, for about a week. This is enough to bring me from 18 degrees to 4. It just takes longer.
The reason I do it this way is because of what happens to yeast when it gets stressed. When yeast gets stressed (such as, when the temperature changes abruptly) it produces a variety of stress compounds in the form of phenols and other off-flavor chemicals. It's rather like a human being that's suddenly been confronted with a stressful situation: These chemicals are the yeast equivalent of cold sweat. By gradually reducing the temperature in small increments I strive to minimize this effect by letting the yeast acclimate and fall asleep gently, rather than shocking them into a comma.
Is this a better approach than cold crashing? I have no idea. I have heard claims that when you cold crash your yeast falls asleep so fast that it doesn't have time to produce off-flavors in significant quantities. I don't know. One of these days I may try this: Take a batch, split it in two, and let half cool in the house fridge (at 4C) while I cool the other half slowly. It will be interesting to see the difference.
My philosophy of brewing is that you can't rush good beer, and therefore you should avoid doing anything abrupt to it. This is a luxury that we, as home brewers, have over commercial brewers. We can afford to wait the extra few days. We can age a beer for a year before we crack open the first bottle. We can experiment much more readily with our 20 liter batches than they can with their 200 or 2000 Liter batches. Given all that, it seems only natural to avoid doing something fast and brutal to your yeast, and prefer instead a slower, gentler process. But then, that may just be me.
One of the methods that we use to achieve this lofty goal is Cold Crashing.Cold crashing is a process by which we take the beer once it's done fermenting, and abruptly drop the temperature in the fermentor from the blissful 17-21C of ale fermentation to a blistering 4C for about two days. (Lager, being laggered at 4C anyway is not cold crashed. Or if you will, Cold crash is part of its basic process.) The idea is that the yeast will become dormant and flocculate out of the beer, leaving it clear. A secondary use of cold crashing is to stop fermentation before it is complete, in order to leave more sugar in the beer and a lower alcohol content. (This is kind of a misconception, since you don't stop fermentation, you suspend it, and the yeast will take it back up if you raise the temperature again)
Personally, I can never bring myself to cold crash a beer, and instead I prefer a slower process in which I drop the temperature by about 1 degree C every 12 hours, for about a week. This is enough to bring me from 18 degrees to 4. It just takes longer.
The reason I do it this way is because of what happens to yeast when it gets stressed. When yeast gets stressed (such as, when the temperature changes abruptly) it produces a variety of stress compounds in the form of phenols and other off-flavor chemicals. It's rather like a human being that's suddenly been confronted with a stressful situation: These chemicals are the yeast equivalent of cold sweat. By gradually reducing the temperature in small increments I strive to minimize this effect by letting the yeast acclimate and fall asleep gently, rather than shocking them into a comma.
Is this a better approach than cold crashing? I have no idea. I have heard claims that when you cold crash your yeast falls asleep so fast that it doesn't have time to produce off-flavors in significant quantities. I don't know. One of these days I may try this: Take a batch, split it in two, and let half cool in the house fridge (at 4C) while I cool the other half slowly. It will be interesting to see the difference.
My philosophy of brewing is that you can't rush good beer, and therefore you should avoid doing anything abrupt to it. This is a luxury that we, as home brewers, have over commercial brewers. We can afford to wait the extra few days. We can age a beer for a year before we crack open the first bottle. We can experiment much more readily with our 20 liter batches than they can with their 200 or 2000 Liter batches. Given all that, it seems only natural to avoid doing something fast and brutal to your yeast, and prefer instead a slower, gentler process. But then, that may just be me.
Thursday, October 6, 2011
My cider will kick your beer's butt!
I made hard cider a couple of weeks ago.
I made cider because brewing all grain is a lengthy process, and I'm not allowed to do it until the baby comes. I brewed a couple of extract beers in the meantime, which was kinda nice (like going back to a family sedan after a long time or riding a motorcycle) but boring. So I moved on to other alcoholic beverages.
Cider is remarkably easy to make. You mix apple concentrate with enough water, add sugar, boil a bit, cool, and pitch. That's it. Of course, never content to do things the easy way, I ended up adding not quite enough water, and added in all the inverted sugar I had on hand (about half a kilo, to an 8liter batch) and so I ended up with cider that had a starting gravity of 1.079. Given that I could expect it to drop to about 1.005 if I let it ferment all the way, I was looking at almost 10% ABV. A bit high for a fruit drink. It would be better if I could stop the fermentation before it went all the way.
One way to stop the fermentation, or at least to dramatically reduce it, is to keep the drink cold, and remove as much of the yeast as you can. Of course, you can't go in there with a sieve and fish the yeast out, but it turns out that if you cool the liquid, the yeast will go dormant and fall out of suspension. Which is a win win situation, if you can get the thing cold enough. 4-5 degrees C ought to do the trick. This is called "Cold crash".
Ah, but there's a problem: My fridge, which has been the subject of much consternation lately, is nowhere near that cold. And given that it is currently fermenting lager, it shouldn't be that cold. What can you do?
Enter the MLCS-7 Massive Liquid Cooling System. Also known as "my mash tan cooler, with about 7 liters of ice:
I have a pretty small mash tan, but my small fermentator fits in it perfectly. I put it in the middle, put as much ice around it as I could (in re-freezable plastic bottles) and topped it off with cold tap water. To carry the heat better I connected my pump to circulate the water from the bottom of the tan back on top. This turn out to be completely unnecessary as, within 12 hours, the temperature of the water dropped to an incredible 1.3 degrees C - my actual fridge doesn't get that cold!
After about 42 hours the cider was so thoroughly cold crashed that it had virtually gone through the floor. I transferred it to a bottling bucket, leaving behind most yeast, added a bit of sugar (totally unnecessary since after the crash it read 1.025, which meant it still had plenty of sugar in it, but old habits die hard) and bottled about 8 liters of golden goodness. It's sweet, eminently drinkable, girls like it, and at 8% Alcohol By Volume it will kick your butt!
As a side note: Heat is energy, and energy can only be transferred, not destroyed. I got a great illustration of this during the cold crash process. I would rotate the ice bottles in and out of the cooler, taking freshly frozen bottles from the freezer, and putting half-thawed bottles back in. As a result, the temperature in my freezer rose dramatically from about 7-8 degrees below to 1-2 degrees below zero, as the freezer worked to dissipate the heat energy that the ice had gathered. Now that I've finished the process, and the freezer doesn't have to deal with the extra heat, the temperature in there had fallen as low as -8.5C. Which is great for trying to lager my lager in the fridge. But that's a different story.
I made cider because brewing all grain is a lengthy process, and I'm not allowed to do it until the baby comes. I brewed a couple of extract beers in the meantime, which was kinda nice (like going back to a family sedan after a long time or riding a motorcycle) but boring. So I moved on to other alcoholic beverages.
Cider is remarkably easy to make. You mix apple concentrate with enough water, add sugar, boil a bit, cool, and pitch. That's it. Of course, never content to do things the easy way, I ended up adding not quite enough water, and added in all the inverted sugar I had on hand (about half a kilo, to an 8liter batch) and so I ended up with cider that had a starting gravity of 1.079. Given that I could expect it to drop to about 1.005 if I let it ferment all the way, I was looking at almost 10% ABV. A bit high for a fruit drink. It would be better if I could stop the fermentation before it went all the way.
One way to stop the fermentation, or at least to dramatically reduce it, is to keep the drink cold, and remove as much of the yeast as you can. Of course, you can't go in there with a sieve and fish the yeast out, but it turns out that if you cool the liquid, the yeast will go dormant and fall out of suspension. Which is a win win situation, if you can get the thing cold enough. 4-5 degrees C ought to do the trick. This is called "Cold crash".
Ah, but there's a problem: My fridge, which has been the subject of much consternation lately, is nowhere near that cold. And given that it is currently fermenting lager, it shouldn't be that cold. What can you do?
Enter the MLCS-7 Massive Liquid Cooling System. Also known as "my mash tan cooler, with about 7 liters of ice:
I have a pretty small mash tan, but my small fermentator fits in it perfectly. I put it in the middle, put as much ice around it as I could (in re-freezable plastic bottles) and topped it off with cold tap water. To carry the heat better I connected my pump to circulate the water from the bottom of the tan back on top. This turn out to be completely unnecessary as, within 12 hours, the temperature of the water dropped to an incredible 1.3 degrees C - my actual fridge doesn't get that cold!After about 42 hours the cider was so thoroughly cold crashed that it had virtually gone through the floor. I transferred it to a bottling bucket, leaving behind most yeast, added a bit of sugar (totally unnecessary since after the crash it read 1.025, which meant it still had plenty of sugar in it, but old habits die hard) and bottled about 8 liters of golden goodness. It's sweet, eminently drinkable, girls like it, and at 8% Alcohol By Volume it will kick your butt!
As a side note: Heat is energy, and energy can only be transferred, not destroyed. I got a great illustration of this during the cold crash process. I would rotate the ice bottles in and out of the cooler, taking freshly frozen bottles from the freezer, and putting half-thawed bottles back in. As a result, the temperature in my freezer rose dramatically from about 7-8 degrees below to 1-2 degrees below zero, as the freezer worked to dissipate the heat energy that the ice had gathered. Now that I've finished the process, and the freezer doesn't have to deal with the extra heat, the temperature in there had fallen as low as -8.5C. Which is great for trying to lager my lager in the fridge. But that's a different story.
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