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Author Topic: Ales exclusively thus far... Time to brew a lager!  (Read 2814 times)

Offline Stevie

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Ales exclusively thus far... Time to brew a lager!
« Reply #15 on: October 17, 2015, 07:14:13 am »
Air is not a good insulator when compared to water. Look at coolers. All goes to hell when some idiot drains the melted water from the cooler. All that does is make the new ice melt faster.

You're example is flawed as it has an insulated bag. That's the key to your idea, not the air. And I still don't understand how your magic sleeping bag only takes a bottle a week when my chest freezer runs multiple times a day, even with a thermowell measuring the exact temp of the beer.

Using a cooler for a water bath is even better, but I think the biggest issue with water baths is the open surface. And like I said before, to work well, one needs to start with cold wort and cold water. Lowering wort 20° with either method isn't practical.
« Last Edit: October 17, 2015, 07:21:58 am by Steve in TX »

Offline HoosierBrew

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #16 on: October 17, 2015, 07:44:56 am »
Yep. Using the bag is the X factor, not the air. When I used a tub of water with frozen water bottles I had fermometers stuck to the buckets, which are accurate to a couple degrees F.  The temp of the beer in the bucket was always within a couple degrees of the fermometer reading. So I added frozen bottles until the fermometer was in the range I wanted. As said, I wasn't trying to cool 20 deg F. I cooled the wort to target pitching temps and used the tub/bottles to maintain that within reason. I medaled on a lager doing this, with comments on 'clean fermentation', so I was doing something right. Don't get me wrong - I love my fridge/temp controller but it worked pretty well. I think Denny would agree - he did it for a long time.
Jon H.

Offline charles1968

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #17 on: October 17, 2015, 09:34:09 am »
Air is not a good insulator when compared to water. Look at coolers.

The wall of a cooler uses air for insulation. You're confusing insulation and thermal mass. Filling a cooler with water increases thermal mass, but the insulation comes from the air.


You're example is flawed as it has an insulated bag. That's the key to your idea, not the air.

The bag insulates because its filling contains air. Fillings like hollowfibre trap a lot of air and prevent it convecting, so there's very little heat transfer. That's how sleeping bags keep you warm and it's also how the wall of a fridge stops heat getting in. The air inside the bag isn't the main form of insulation. You want the air inside the bag to circulate and conduct so that the heat energy in the beer is absorbed by the ice bottle, which will lower the beer temperature.

And I still don't understand how your magic sleeping bag only takes a bottle a week when my chest freezer runs multiple times a day, even with a thermowell measuring the exact temp of the beer.

I use one or two bottles to get the wort down to pitching temp and then change maybe once or twice in the week, so it's not just one bottle for a week. As I said earlier, I've only had to change the bottle once in the last week.

Lowering wort 20° with either method isn't practical.

It is with adequate insulation. A two litre (about 2 quarts) bottle ice from a domestic freezers is a lot colder than freezing temp. They come out of my freezer at -27 Celsius but an average freezer will get ice to -18 Celsius. With perfect insulation that can lower a 5 gallon (19 litre) batch of beer to 7 Celsius (45 Fahrenheit).
http://www.onlineconversion.com/mixing_water.htm

In practice insulation isn't perfect and there's some heat energy from the air inside the bag and the bag itself, so the beer doesn't get quite that cold. Fermentation also creates a bit of heat.

As I said, I've tried both methods. If you've only tried one method and not the other, perhaps give it a go before offering an opinion on whether it works.
« Last Edit: October 17, 2015, 09:46:08 am by charles1968 »

Offline charles1968

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #18 on: October 17, 2015, 09:38:50 am »
Yep. Using the bag is the X factor, not the air. When I used a tub of water with frozen water bottles I had fermometers stuck to the buckets, which are accurate to a couple degrees F.  The temp of the beer in the bucket was always within a couple degrees of the fermometer reading. So I added frozen bottles until the fermometer was in the range I wanted. As said, I wasn't trying to cool 20 deg F. I cooled the wort to target pitching temps and used the tub/bottles to maintain that within reason. I medaled on a lager doing this, with comments on 'clean fermentation', so I was doing something right. Don't get me wrong - I love my fridge/temp controller but it worked pretty well. I think Denny would agree - he did it for a long time.

It's the air trapped in the sleeping bag filling that makes it a good insulator, not the air around the FV - apologies if I wasn't clear on this earlier.

There's no doubt you can ferment lager at the right temperature with a trub of water and ice bottles. But it means changing the ice bottles very frequently as the absence of insulation allows the trub and the FV to warm up. It's a lot of work, but it can be done. A couple of frozen water bottles inside an insulated bag works a lot better and can maintain a much larger difference in temperature between the beer and external environment. I have no problems fermenting lager at 10-12 Celsius in summer with this method.
« Last Edit: October 17, 2015, 09:43:37 am by charles1968 »

Offline charles1968

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #19 on: October 17, 2015, 09:50:26 am »
Just to add - this isn't the first time I've been told on a forum that my method can't possibly work.

I've tried the wet T-shirt method too. Complete waste of time. Evaporation can't maintain a 15-20 Celsius temp difference.

Offline Stevie

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #20 on: October 17, 2015, 09:51:56 am »
I'm not saying it can't work, I'm just disagreeing that water can't act as a good insulator.

Offline charles1968

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #21 on: October 17, 2015, 10:14:14 am »
I'm not saying it can't work, I'm just disagreeing that water can't act as a good insulator.

Water is a good conductor and a bad insulator. The reason a swimming pool at 20 Celsius feels a hell of a lot colder than air at 20 Celsius is because the water conducts heat out of your body faster.

When you stand an FV in a trub of icy water, several things are going on. The water and ice conduct well so chill the FV quickly. The high thermal mass means they are slow to warm up to ambient temperature. But the lack of insulation means they will warm up to ambient over a day or two unless you keep changing the ice bottles. The reason this setup doesn't work well is the lack of insulation.

Offline HoosierBrew

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #22 on: October 17, 2015, 03:31:50 pm »
The reason a swimming pool at 20 Celsius feels a hell of a lot colder than air at 20 Celsius is because the water conducts heat out of your body faster.

Exactly why the tub of water is effective at sinking excess heat from the fermenter. Look, not trying to be argumentative - if there's one theme on this forum, it's that there are multiple ways to make good beer. While more labor intensive than the zip up jacket, I'm just saying that this is a viable option for somebody on a budget (like I was when I started).
Jon H.

Offline charles1968

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #23 on: October 17, 2015, 05:24:48 pm »
Look, not trying to be argumentative - if there's one theme on this forum, it's that there are multiple ways to make good beer. While more labor intensive than the zip up jacket, I'm just saying that this is a viable option for somebody on a budget (like I was when I started).

I would say try both, then see what you think. Maybe next time your fridge is full and you want to chill an FV.

I've crash cooled to 39F in a sleeping bag in order to fine with polyclar. It didn't get quite cold enough to remove chill haze though. For that a fridge is better.


Offline HoosierBrew

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Re: Ales exclusively thus far... Time to brew a lager!
« Reply #24 on: October 17, 2015, 05:30:33 pm »
Look, not trying to be argumentative - if there's one theme on this forum, it's that there are multiple ways to make good beer. While more labor intensive than the zip up jacket, I'm just saying that this is a viable option for somebody on a budget (like I was when I started).

I would say try both, then see what you think. Maybe next time your fridge is full and you want to chill an FV.

I've crash cooled to 39F in a sleeping bag in order to fine with polyclar. It didn't get quite cold enough to remove chill haze though. For that a fridge is better.



May do that. My fermentation fridge gets crowded for space sometimes, with beers in the pipeline.
Jon H.