Single vessel partial mash/kettle question

[Brew Engineer]

Earlier this year, I moved to a Turkey Fryer and full wort boils. I love it. I've also been reading the threads about brew in a bag, and I want to use a variation to do a partial mash in a bag, pull teh bag, then bring to boil, and add my remaining extract.

My question is: How well can I expect to maintain my mash temperature with this method?

I've got a 7 ga aluminum kettle. If I bring it up to strike temp, then "dip in my bag", making sure to fully wet the grains, and let it sit for an hour, I'm expecting to see a significant temperature drop over that time.

Can I turn on the flame if I need a temperatuer boost? I would think that would be hard to control the temp, and I wouldn't want to scorch the grains.

What kind of termperature drops do you see in non-insulated mash tuns? Should I even worry, or will 2-3 degree drops over the course of the mash matter?


Thanks!

[Cosmic Charlie]

Not knowing the answer to your question will not prevent me from chiming in. I do partial mash on the stovetop, and I know the usual suggestion is to check the temp every 5 minutes. When you need to add heat, do so in 15 to 30 second bursts. I would guess that shorter intervals will work with a turkey fryer, but I haven't tried it.

[Bugeater]

For the small volume of a partial mash, you may want to just do that portion inside on the stove. This will give you a little better control over the heat than what you would have with that turkey fryer burner.

Wayne
Bugeater Brewing Company

[ColdBraue]

I would say that you should get some reflective insulation from the hardware store and make a jacket for the kettle and the lid. Make it removeable. That way you could bring it to temp, throw the jacket on, leave it for an hour and most likely only lose a couple degrees. You could even fire the burner for a minute at the half hour mark to combat the heat loss.
You could also go ahead and do the partial mash in your 5 gal kettle (I'm assuming you still have it from the pure extract days) in the oven.
Cheers!

[dre]

I do my partial mashes in a small 2 gallon beverage cooler. Use the large grain bag you probably already have. Pull the bag out, dump liquid into your boil kettle. Or a separate pot so you can bring the water in the boil kettle up to sparge temps and sparge the grains.

Temperature drop over the hour of mashing is a 2-3 degrees.

[Thirsty Boy]

I'm going to assume that the reason you want to do this partial mash in your actual boiler, is, in a similar manner to the BiaB method, you want to have all your water in there in the first place. To avoid the need for separate vessels??

Right? If not, then what the other guys have said is probably better advice. If so.... then -

Wrap that pot up in some insulation and it should only drop a few degrees over the hour - in exactly the opposite way to what Bugeater was saying about small volumes, the large volume involved in having all the water in there means it holds its temperature more evenly. Also, because your mash is going to be very thin, even by BiaB standards, you will be able to add heat pretty easily if you do lose some. Check it after 5 mins, then every 15. Add some heat if you need to.

You will be pushing the envelope a bit though... all the things that people think will go wrong when you BiaB, well you are only going to be more at risk of them being right with the even thinner mash.

Having said all that - I would like to ask why? Why do the partial? If you have the pot, you have the burner & you have the bag - just do it AG. It will take precisely zero minutes longer than if you do a partial with extract, will be absolutely no harder and will be cheaper. Just throw in a couple more kilos of crushed grain and leave out the extract... otherwise do exactly what you were going to do anyway.

Thats the whole point of BiaB ... its actually easier to do AG than a partial mash

Thirsty

[Brew Engineer]

Thanks Thirsty Boy-

I've done extract with steeping grains for several years. There are a few styles, however, that I need to do either all grain, or partial mash. I'm trying to avoid (or minimize) any additional investment right now.

My kettle is a 7 gallon turkey fryer, which is barely big enough for a full wort boil now. I don't think I could fit a full mash, and the total amount of water in it at the same time. Plus, I still really enjoy doing extract brews ( I know I'm in the minority), but they are so much easier. I don't have to worry about sparging, and efficiencies. And there's less time and mess than with the traditional mash tun set-up.

So, I'm looking for a cheap and easy way to dip my toes in the mash tun, so to speak.

[Thirsty Boy]

Plus, I still really enjoy doing extract brews ( I know I'm in the minority), but they are so much easier. I don't have to worry about sparging, and efficiencies. And there's less time and mess than with the traditional mash tun set-up.

So, I'm looking for a cheap and easy way to dip my toes in the mash tun, so to speak.

See the last line of my previous post - All Grain via BiaB is easier and more simple that Partial Mashing. It would be going too far to say its easier than extract with steeping grains.... but its certainly right behind it giving it a nudge

You do need a big pot though - 35L would be the around minimum for a 19-20L batch of 1.050 beer, stronger or bigger batches need a bigger pot. A converted 50L keg will brew a single batch of pretty much any beer - you would need around a 75L pot for double batches.

A cheap and easy way for people to dip their toes into the mash tun was exactly the reason the BiaB was invented. The whole way it works was designed to make it an attractive alternative to Partial Mash brewing. It is quite deliberately, a gateway drug for AG.

Anyway, sorry to evangelize. I will shut up now

Thirsty