Insulation vs. Low Heat?

[tsholl]

Looking to start BIAB after about ten extract batches. I am curious about all the talk about insulation to keep the wort at a proper temperature during mashing. Why couldn't you just keep your heat source (stove in my case) on low to keep a constant temp, monitoring the temp and adjusting as needed?

Is it because...
1. That would burn your bag
2. You don't want to have to stand there and monitor the temp for an hour
3. Some other reason?

If I kept the bag like an inch off of the bottom of the kettle and don't mind monitoring the temp for an hour, is this an option?

Also any tips on converting 5 or 10 gallon all grain recipes to 1 gallon recipes would be appreciated! I'm moving to NYC so think I'm just going to be able to do 1 gallon batches in my tiny apartment.

 

[cswant88]

If you keep the bag off the bottom and apply very low heat, it’s doable. I started all grain doing 1 gallon batches on an induction plate. I used a stainless cooling rack to keep the bag and grains off the bottom. Once I mashed in, I dropped it to minimum power, 200 watts, and put the lid on and it maintained exact temp for the whole hour.

 

[cswant88]

Also, I use BeerSmith. You can plug in your fermentables as percentages, and scale it down to your 1 gallon equipment profile while maintaining OG. You can do the same with the hops and adjust to keep the IBUs about the same.

 

[mongoose33]

One of the things you'll find about applying heat to the bottom of a kettle of mash is the heat will not move upward very readily. Thus, you'll be warmer than you intend on the bottom, and colder than you intend on the top. To address that you have to stir a lot if you're going to get that heat to spread around.

Easier to insulate well, IMO.

 

[RM-MN]

Ask yourself what happens during that hour long mash.

The main reason for the mash is to allow the enzymes to convert the starches to sugar. That happens as soon as the starch is gelatinized which happens at a varying rate which depends on the size of the grain particles. The grain particle size is the restriction on filtering the wort from the mash and on a conventional mash tun that particle size has a lower limit which then means one must wait longer for the starches to be exposed and converted.
With BIAB the particles can be much smaller as one uses the bag for the filter, not the grain particles. With that smaller particle size, the starches are exposed much quicker and conversion happens fast. That means you don't need the temperature constant for a whole hour which then negates the need for heating. Just bring the water to strike temp, stir in the grains, and cover the kettle. Be sure to give the mash long enough to extract the flavors too as that takes more time than conversion but doesn't require tight temperature control. I rarely mash for more than 30 minutes anymore and know that my conversion is complete well before that.

 

[LittleRiver]

....If I kept the bag like an inch off of the bottom of the kettle and don't mind monitoring the temp for an hour, is this an option?...

Sure it is, if that's what makes you happy. If so, you may also enjoy grinding grains by smashing them with a hammer one grain at a time.

Seriously now, insulating the kettle just makes sense. It's the easiest and most efficient way to maintain mash temps. No extra power/fuel required, no additional items to clean, no need to stand there and monitor it, etc.

...I'm moving to NYC so think I'm just going to be able to do 1 gallon batches in my tiny apartment.

For small batches like that, pre-heat your oven (assuming you'll have one), turn it off, and put your pot in the oven during the mash to maintain temp.

 

[tsholl]

For small batches like that, pre-heat your oven (assuming you'll have one), turn it off, and put your pot in the oven during the mash to maintain temp.

Nice, I like the oven idea. I will go with that. I'm just trying to minimize the amount of equipment I need with limited storage space, even if that is just a ratty sleeping bag or blanket I use for insulation.

 

[Mic Carp]

I just recently started biab and live in so cal so i am a stranger to winter and i also brew outside all year, but in my limited BIAB experience, using a cheap faux down comforter and heavy quilt draped over the kettle (5 gallon batch, 6.5 gallon preboil) i lose only 2-3 degrees in an hour. I would suspect that indoors your home is at a comfortable temp so even with smaller volume, you could expect pretty similar results. And as mentioned previously, after the first 25 minutes or so it’s no longer temp critical.
Relax and have a homebrew
Cheers

 

[BandonBrewingCo]

Just beware that smaller volumes will lose temp quicker but like others said, in BIAB maintaining mash temp for so long isn't an issue. Might be an issue for 1G batches though...

 

[bluedaisy0627]

I BIAB 2.5 gallon batches. I wrap it up in a 0° sleeping bag. My husband does 5 gallon BIAB and also uses the 0° sleeping bag. Neither of us have had any issues with losing more than a couple of degrees in an hour.

 

[RPh_Guy]

When I first started, I was applying heat during the mash. It was basically impossible to keep temperature consistent.
Insulating provides a lot more control & consistency, besides being easier.

 

[derekp83]

I tested my kettle with just 1.5 gallons of water the other night; no grains. I brought the temp up to around 159 degrees F (I know that's high, but it's not the point) I checked after 45 minutes and had lost about 15 degrees. Will I lose less degrees with 2 lbs of grains in the kettle?

 

[mongoose33]

I tested my kettle with just 1.5 gallons of water the other night; no grains. I brought the temp up to around 159 degrees F (I know that's high, but it's not the point) I checked after 45 minutes and had lost about 15 degrees. Will I lose less degrees with 2 lbs of grains in the kettle?

Did you insulate it? How?

How big is the kettle? Did you cover it with a lid? How much room was left in the kettle after you added the water?

Yes, you'll lose less with the grain in it. The trick is to have relatively little headspace, and insulate well.

 

[derekp83]

Did you insulate it? How?

How big is the kettle? Did you cover it with a lid? How much room was left in the kettle after you added the water?

Yes, you'll lose less with the grain in it. The trick is to have relatively little headspace, and insulate well.

Lid on, but no insulation. When my kettle has 1.5 gal in it, there's very little headspace.

 

[wilserbrewer]

A good way to maintain mash temp with a smaller kettle is to place the mash in a warm oven.

Preheat oven to lowest setting. put the mash in and turn oven off. Take a nap for an hour...

 

[derekp83]

A good way to maintain mash temp with a smaller kettle is to place the mash in a warm oven.

Preheat oven to lowest setting. put the mash in and turn oven off. Take a nap for an hour...

Interesting idea. My oven can only go as low as 170, but as you said, turning it off, it might be a decent way to accomplish a stable mash temp.

 

[deeve007]

I love the oven idea, I'm only doing a 10L batch first few times in a 20L pot that can just fit in the oven...

 

[Cevan65]

I brew 2.5 gallon batches (26 so far). I’ve got about 3.5 gallons of water and 7 lbs of grain in a 5 gal pot. I use two layers of that plastic insulation you can get at Home Depot cheap and a couple layers on the lid. My mash is 45 minutes. I’ve never lost more that a couple of degrees.

 

[odie]

I have about 3 wraps of that silver bubble wrap stuff you get at home depot or lowes. works great to retain mash heat and the boil. after boil I remove the wrap to speed cooling.

 

[enkamania]

I use a water heat blanket wrapped around the kettle and a collection of old towels, blanket and sleeping bag.

 

[bracconiere]

Interesting idea. My oven can only go as low as 170, but as you said, turning it off, it might be a decent way to accomplish a stable mash temp.

I love the oven idea, I'm only doing a 10L batch first few times in a 20L pot that can just fit in the oven...

i modded my oven to as low as 95f with a 200ohm resistor on the temp probe....

 

[lump42]

A good way to maintain mash temp with a smaller kettle is to place the mash in a warm oven.

Preheat oven to lowest setting. put the mash in and turn oven off. Take a nap for an hour...

I started with Brooklyn brewshop 1-gal recipes. A I mashed into an enamel cast iron dutch oven. I would pre-heat the oven on lowest setting, turn the oven off, and stick the dutch oven in for an hour. At most it only raised the mash temp 2-3 degrees. Then I laddeld the whole mash into a colander over a second pot. That's before I found out about BIAB. Now when I do small batches, I just lift the bag out. Paint strainer bags have worked for 1-3 gallon BIAB batches for me.

 

[Immocles]

2.5G batches as well.
I line a clothes basket with a towel or two, plop the kettle in it, then wrap the kettle in my winter robe. I get a little cold sometimes, but the mash doesn't.

 

[Carolina_Matt]

after boil I remove the wrap to speed cooling.

Wow, that never crossed my mind but it makes sense! I use a Digiboil with the neoprene jacket, and I keep it on during the entire brew day. It never occurred to me that I should take the jacket off when I'm using my wort chiller. I'll give it a shot next time!

 

[Kenmoron]

I do BIAB 3 gal batches in a 5 gal kettle on my stovetop. Before I mash in I hit "keep warm" on my oven and let it heat up for about 5 min. After I mash in I stick the kettle in my oven and turn off the keep warm function. Sometimes I can keep the same temp for the entire 60 min, and usually never loose more than 2-3 degrees. I've found that if I keep the oven on then my mash temp starts increasing. I'm assuming my keep warm function on my oven is near 200F. So just a quick keep warm preheat gets the job done almost perfectly.

 

[Mer-man]

Just beware that smaller volumes will lose temp quicker but like others said, in BIAB maintaining mash temp for so long isn't an issue. Might be an issue for 1G batches though...

Cork is ok, but Kinsale is where it's at. I was just there for the Jazz Weekend

 

[BandonBrewingCo]

Cork is ok, but Kinsale is where it's at. I was just there for the Jazz Weekend

Kinsale is in Co Cork ;-)

Ya Kinsale is great for events. Being from Copenhagen, if you're into sailing, West Cork in general should be right up your street.

Back on topic (kind of), Cork city is great for craft beer!

 

[Saunassa]

I do 5.25 gal batches in an 8 gal kettle out n the garage. Temp 30f out there. I just shut off the burner, wrap the whole thing burner and all in one of my wife's big bath towels (shush) and then an old comforter tucking it in beneath and drop an old blanket over it. within a degree at 20 minute stir. Loose 3-4 degrees by end of 60 minutes. Next time I will do the 20 Minute stir, take a sample for ph and not open again till end of 60 minutes. See what temp loss is then.

 

[odie]

Wow, that never crossed my mind but it makes sense! I use a Digiboil with the neoprene jacket, and I keep it on during the entire brew day. It never occurred to me that I should take the jacket off when I'm using my wort chiller. I'll give it a shot next time!

Think about it. A metal kettle is just a big radiator. Let it radiate that heat out