BIAB Partial Mash W/Oatmeal

[rodwha]

I had brewed an oatmeal coffee stout that turned out terrible as it didn't completely ferment out and is sweet, and doesn't have a head.

Rereading How To Brew again and I'm seeing something about a protein rest, especially when mashing unmated grains above 25%. I have no idea what typical 2-row is, but I'd think it's malted. And does crystal malts, carapils, chocolate malt, and roasted barley count towards the percentile mentioned? The oatmeal was 30% of the mash.

What I've been doing is heating my water to ~165* and adding my grains and then trying to keep my mash temps (I use 2 thermometers, one in the center and pushed down to the bottom, and the other along the edge and in the middle) no higher than 160* in the middle and no lower than 145* on the side, though this isn't easy and so the temps can get 5* beyond their limits.

I usually mash 90-120 mins as well as my temps often get a bit too low and so I add time.

When I have about 10 mins left I heat up my water in 4 pint glasses in the microwave (~150*) and place the grains in a colander to drain a bit followed by a pint and a squeeze with the spoon. After all of that I place it into a pot to finish gravity draining and pour that in while I'm boiling.

I intend to try again with oatmeal, wheat berries, and rye. Will I need to do things differently?

 

[RM-MN]

What are you mashing in that you get that much difference in temperature? How well are your grains milled? How much are you brewing at a time?

With your grains milled reasonably well, you don't need to mash for 90 or 120 minutes, 30 to 60 should be plenty. There are 2 enzymes that work on the starches in the grain to turn that starch to sugar. To make your wort more fermentable you want both enzymes to work at the same time. For that you really want a mash temp of 152 to 154. If your mash got over 160, you pretty much stopped the enzyme that makes fermentable sugars and that would make you beer too sweet.

 

[freisste]

I have to assume this is a relatively small batch considering it is BIAB and you are sparging with such a small amount of water.

Why do you have so much temperature variation? Make sure to stir really well to not only get even temperatures, but also to ensure the grains are all wetted.

Then insulate your pot, if possible. Or another option (my personal preference) is to put the pot in the oven set to the lowest setting. Take it out every 20 minutes to stir and you should have no efficiency issues or issues holding temperature.

Good luck.

 

[signpost]

Yes, stir that mash like crazy.

When you think you've stirred it enough, stir it some more.

Then, after you've done that, stir it again for good measure.

 

[gregfreemyer]

Shouldn't your sparge water be about 170 (but below 175).

Also 2-row is a base malt, so it is malted. But the oats typically aren't and they were 30% of your grain bill all by themselves.

 

[rodwha]

I am mashing in my 5 gal aluminum brew pot.

When I stir it drops my central temp down into the 140's. That's why I extend my mash time.

My grains are milled by the HBS.

I am topping off to make 6 gals and mashing as much as 8 lbs.

I shoot for 153-4* but it's nearly impossible.

I cannot put my pot in the oven as it has plastic on the handles. I've been eyeing an 8 gal aluminum pot w/o plastic.

I'm basically just rinsing the remaining sugars with the 2 qts, and probably not using enough.

I'm often getting between 70-80% efficiency partly due to 40-60% extract. I base that by reducing the efficiency # in the calculator until the gravity matches.

I certainly ensure all of the grains are wetted. I use 1.5 qts/lb.

I have been considering what I could insulate my pot with that won't catch on fire or get in the way. I can't bring myself to tear up one of my sleeping bags though.

 

[rodwha]

I've read that the sparge water doesn't really need to be hot.

 

[rodwha]

My very first partial mash was a rye pale in my 2 gal Igloo. I preheated it with nearly boiling water, and it still didn't hold the temp well. After 30 mins I checked on it and it had dropped to something like 140*.

 

[gregfreemyer]

I've read that the sparge water doesn't really need to be hot.

I've read that if you pull the bag at 150 or so a lot of the extracted fermentables stick to the grains because it is so viscous (sticky). The hotter the sparge water the better job it does at reducing the viscosity and thus getting the fermentables to release from the grains. The only negative with heating your sparge water a little more in the microwave is you want to keep it below 175 during the sparge.

 

[rodwha]

What might be an optimal temp to shoot for? 175* knowing they are cooling while I'm dealing with one at a time?

I suppose I ought swipe the other two plastic pint glasses for sparge service too and see how long they need to be heated for.

 

[speeddemon190]

What I do for my stove top all grain and partial mashes (thank you deathbrewer) is the following.

First I calculate how much total grain bill I will have lets say 10lbs.
I then use the following calculator (http://www.rackers.org/calcs.shtml) to figure out my grain to water ratio that will come as close to 5gal as possible ( I usually shoot for 4.5gal under the will it fit section)
I then calculate my strike water temp with the included calc on that page. It will show you what to preheat your strike water to so that when you add your grain the temp will drop to your ideal mash temp.
If you can fill your 5 gal pot as close to the top with grain you will see less heat loss during the mash. My process is once my desired strike temp is reached I pour in about 1/4 of my grains and stir like crazy to get them all seperated and thoroughly soaked then I proceed and pour the rest of the grain in at 1/4 increments until its all soaked and seperated. Then I put the lid on and let it sit for 20 min. open and stir, close and wait another 20 min before stirring again.

In the meantime I calc how much sparge water to use ( I dunk sparge) so if i have a 10 lb grain bill with a water/grain ratio of 1.5qt/lb means there will be 3.75 gallons (15 quarts) in the mash. The grain will absorb 0.125 qt/lb (1.25 gallons) so after you take your grains out there will only be 2.5 left in the pot. I usually do a partial boil of 3.5 gal so i will need to make up 1 gallon.....so with the last 20 min of the mash I bring 1 gallon of water to 170 degrees. When the mash is done I take the grains out and dunk them in the 170 degree gallon of water for 10 min or so and then let them drain into the pot. add the 1 gallon of sparge water to the main boil kettle and continue as normal.

With this process (mind you its BIAB) I only loose about 2 degrees in a 60 min mash. Read the following write ups...they are fantastic at making the process really easy.

https://www.homebrewtalk.com/f39/easy-stovetop-all-grain-brewing-pics-90132/

https://www.homebrewtalk.com/f39/easy-partial-mash-brewing-pics-75231/

 

[rodwha]

Deathbrewer's thread is what got me doing a BIAB.

Thanks for linking it as it's been some time, and I can obviously use some help.

I read a few of the posts, and the one about putting the lid on scares me. I have to stir about every 5 mins as my temp creeps up quickly.

Basically I stir when I'm around 160* in the middle, which drops the temp way down to about 147-151* in the center, which means the exterior is much cooler, often about 20*.

I've tried low heat and no heat, but it's just a constant need for attention.

And this is what has me wondering about an insulation wrap. Something inexpensive (I have $70/mo for hobby $$$ and don't want to spend it all on a wrap). I've been thinking about cutting up an old blanket as SWMBO can stitch it for me. Maybe use some elastic.

 

[rodwha]

I have a quilt I was given from when I was a kid. I'm going to repurpose it and create a thermal blanket out of it. Until I'm actually ready to have it sewed with elastic I'll just use chip bag clips.

I'm guessing, after I get the grains well stirred and the temp back to where I want it (I'll shoot for 155*), I ought to put the lid on and turn the heat off.

How long does it generally take for the heating element to cool enough so that it's not adding heat? In other words how long would you keep an eye on it before you felt comfortable placing the lid on it? I usually have it set low between 2 and 3 with high being 9.

 

[rodwha]

Anyone have an answer for this:

And does crystal malts, carapils, chocolate malt, and roasted barley count towards the percentile mentioned?

 

[chickypad]

And does crystal malts, carapils, chocolate malt, and roasted barley count towards the percentile mentioned?

Those grains are malted but have no diastatic power, so should be counted in the specialty grain total. So if you had 30% oats plus all those specialty grains you may not have had enough base grain to convert. I would try to aim for at least as much base grain as specialty grain in a partial mash.

What I've been doing is heating my water to ~165* and adding my grains and then trying to keep my mash temps (I use 2 thermometers, one in the center and pushed down to the bottom, and the other along the edge and in the middle) no higher than 160* in the middle and no lower than 145* on the side, though this isn't easy and so the temps can get 5* beyond their limits.

I think this is your problem, it sounds like you are not getting the mash well equilibrated from the start. It should not be that difficult to maintain temps, and if you had the same trouble even using a cooler something is not right. The strike water should be hot enough so that after stirring for a full 5 minutes your mash is at an even temp and holding at multiple places around the pot. If you are getting variation you need to keep stirring. If too much stirring at the beginning drops the temp too low then your strike water is not hot enough. Once you have very stable temp if you wrap the whole thing in a bunch of towels or blankets you should only lose a few degrees over the course of the hour. When doing this technique I do not stir during the mash time, you only lose more heat that way.

 

[rodwha]

I usually use at least the same amount of 2-row, and in this case used an extra 1/4 lb.

I thought that you didn't really want to get the strike water to 170* or more, which is why I've brought it up to 165* to start.

If nothing else maybe I could get a hand towel damp with hot water and wrap my grains to warm them up while I'm heating my strike water so it's not quite so dissimilar. And I mean leaving them in the plastic bag while doing so.

 

[chickypad]

My small all grain batches are typically 6-7 lb of grain in a 5 gal pot, which sounds like about the same size as your partial mash. I don't usually need to go over 165* for strike but that's also mashing on the thin side. I wouldn't worry about going higher if you need it. You can also have some boiling water on hand in case you undershoot.

 

[RM-MN]

You really need to use a calculator to determine what your strike temperature should be instead of just guessing and trying to maintain with the burner. I use this one. http://www.tastybrew.com/calculators/infusion.html

I brew on an electric stove and bring my water to the calculated strike temp, turn off the burner, take the lid off, drop in the bag, stir in the grains, and put the lid back on. I'll be within one degree of my intended mash temp then. If I wrap the pot with a bath towel it will remain within one degree of that temp for the full 30 minutes of the mash period. I add no heat until the grains are removed from the pot. I tried using the burner to keep the temperature correct for one batch. Only one batch because I had the same trouble as you with temperature fluctuations.

 

[rodwha]

I just figured the strike temp for 6 and 8 lbs of grains and it came up as 164.7* for either, which is about what I've started at.

Would there be any problems with getting a hand towel wet and microwaving it to get it very hot and then wrapping it around my grains in the plastic bag they come in? It seems thought ought to help tremendously.

 

[RM-MN]

I just figured the strike temp for 6 and 8 lbs of grains and it came up as 164.7* for either, which is about what I've started at.

Would there be any problems with getting a hand towel wet and microwaving it to get it very hot and then wrapping it around my grains in the plastic bag they come in? It seems thought ought to help tremendously.

The strike temperature calculators take the quantity of water and the temperature of the grains into account when they predict the strike temperature. When you mix them into the water they will all be heated and mixed into a single temperature mix, the mash temperature. You shouldn't need to do anything else.

 

[rodwha]

My aluminum pot is a rather cheap thin one. I assume it's a weak point.