Heating a Mash

[TheCrowsNest]

I fly sparge and have been trying to increase our efficency from 65% for several months now. I use a false bottom setup in a plastic keg for mashing.

I've heard that heating a mash up to 168F right before the sparge can help in increasing efficiency. Since we're in a plastic keg, we can't put the mash over heat. For those that have experience fly sparging, have you ever heated up the mash right before the sparge and if so, how did you do it?

I'm thinking that we just add water, but temperature math is not my strong point: how much water do I need, and at what temp, to increase a mash of 3.7 gallons of water, with 12.5lbs of grain, that's at 154F to 168F?

Sorry if this doesn't make any sense, I'm a little lost. Any help on this is appreciated!

 

[cvstrat]

You add boiling water. Use a mash temp calulator to tell you how many gallons of boiling water you need to hit your target temp. Step mashing has historically been used to increase conversion of certain types of malts. Most malts will convert just fine w/o a step mash, but it's worth a shot. I've ultimately eliminated the step from my process as I didn't feel like it added anything to my finished product.

http://www.brewersfriend.com/mash/ has a calc that you can use to figure out how much boiling water you need to hit any specific temp.

Odds are you'll find something else is the culprit in the low efficiency is my guess.

 

[Scut_Monkey]

The options for heating up the mash include
1. Direct heat (not an option for you)
2. High temperature water additions
3. HERMS - this is basically recirculating the wort to a heat exchanger to raise the temp.
4. RIMS - this is basically recirculating the wort to a heating element to raise the temp.
5. Decoction
6. Anything else I forgot

The whole idea behind doing a mash out at 168 is to denature the enzymes working on the wort and to increase the solubility of the sugars in the wort. By denaturing the enzymes the profile of the mash will not change regardless of how long it takes for you to drain the mash tun. By increasing the solubility of the sugars they will flow out of the grain easier which helps you to increase efficiency.

For your setup perhaps a hot water addition would be best. How much water to add for the specs you have is also not my strong point which is why brewing software calculates this for you with accuracy. (This is my cop out answer of the day).

 

[DeafSmith]

The options for heating up the mash include
1. Direct heat (not an option for you)
2. High temperature water additions
3. HERMS - this is basically recirculating the wort to a heat exchanger to raise the temp.
4. RIMS - this is basically recirculating the wort to a heating element to raise the temp.
5. Decoction
6. Anything else I forgot

7. Copper coil "heat stick". I quit using my prechiller because I realized that recirculation worked better, so I wanted to find a use for the 20 feet of 3/8 inch copper tubing. I thought about making a HERMS with it, but I was doubtful about the interior of the tubing - I had seen some green corrosion on the outside, which I cleaned off, but who knows what is on the inside. So instead, I made a "heat stick". After I dough in, I start heating about 3 or 4 gallons of water to boiling and connect my tubing to pump the water from the kettle through the copper tubing heat stick and back to the kettle. I already had hose connections on the prechiller/heat stick, so only needed to add a handle. So at mash out, I just turn on the pump and stick the "heat stick" into the mash and move it around a little while it heats. Based on some measurements and calculations I made it is at least as effective as a 1500 watt electric heat stick. Works great, with no worries about electrocution, burning out the element, scorched wort, leaks, flaking JB weld, etc.

 

[TheCrowsNest]

7. Copper coil "heat stick".

deafsmith, that thing sounds sweet! do you have any pictures of this?

 

[Northcalais40]

Go for a quick decoction, meaning that you heat it only to boiling, then return it to your MLT. If it is for mash out, it can be all liquid and little grain. I do this all the time because it allows me to not use water I'd be sparging with otherwise.

 

[DeafSmith]

deafsmith, that thing sounds sweet! do you have any pictures of this?

I don't have any pics, and just found out that all my camera batteries are run down. I have some charging, so I should be able to get pics by tomorrow.

Anyway, this thing is a coil of 3/8 copper tubing, 8 1/2 inches OD, 9 inches tall, 13 coils. I soldered on a couple of 1/2 inch copper straight tubes that I had lying around, one about 2 feet long and the other about 20 inches. These are both mounted vertical, soldered to the outside of the coil - both soldered to the bottom coil and the top coil, and about 90 degrees apart if you were looking down on the top of the coil. I drilled a couple of holes in a 16 inch piece of 3/4 inch CPVC (which I also had on-hand) and mounted it horizontally, with the two vertical tubes coming up through the holes in the CPVC tube. This lets me rest the CPVC tube across the top of my cooler mash tun to support the weight of the coil (it is heavy when full of water). I added another short piece of CPVC over the top of the longer upright to allow moving the coil around while heating. I've only used it once with this handle which works a lot better than what I had, but I may modify it to make it a little easier to get ahold of.

The only problem, besides being heavier and bulkier than a heat stick is that some grain tends to stick to the coils when I take it out of the mash. This isn't a problem if I'm heating for mash out, but if I use it in the middle of the mash to adjust temperature, I like to squirt it with a squeeze bottle of distilled water to get that grain back into the mash. It's really an insignificant amount of grain, I'm sure, but I just hate to waste any of that good stuff.

 

[ajf]

I fly sparge with a false bottom, and always do a mash out. When I started doing this, my efficiency increased consistently by 10%. I thought (at the beginning) that this was because of the increased temperature of the grain bed during the sparge (mid to upper 160's instead of low to mid 150's). I no longer think that this is the reason.
I do the mash out by adding an amount of near boiling water to the mash, and then stirring well for 2 - 3 minutes, then leaving it to rest for 10 - 15 minutes before vorlaufing and starting the sparge.
I usually mash a bit thicker than you (1 qt / lb, rather than 1.2) and use Promash to calculate the volume of boiling water necessary for the mash out. The calculation is always wrong, and leaves the temperature less than the 168 that I shoot for. This is because I haven't accounted for the thermal mass of the MLT. It doesn't seem to make any difference to the efficiency.
I now think that the main reason for the increase in efficiency is because the mash out addition is stirred into the mash, and the stirring loosens and dissolves sugars that would otherwise remain trapped in the grains. This extracts more sugars at the start of the sparge, and makes the sparge more efficient because there are fewer sugars left to be extracted during the sparge.
For a 12.5 lb grain bill mashed at 154F with 3.7g water, you would need about 6 qt of boiling water to raise the temperature to about 165F (assuming your MLT is similar to mine.

-a.

 

[DeafSmith]

CrowsNest - here's a pic.



It's not real pretty - the coil, which was originally used as a prechiller, was soldered together out of about 4 separate pieces of copper tubing, and I've modified how the handle was soldered on, so there's a lot of solder blobs here and there, plus I'm not real good at soldering. To use it, I lay the horizontal piece across the top of my cooler mash tun in just about the orientation shown in the pic with the hoses coming off to the right. I mounted the handle to the left and back so I could put a paddle down the center and stir while heating. I can use the vertical handle at the top to tilt the coil and move it to different parts of the mash - the bottom of the coil almost, but not quite, touches my false bottom.

 

[Rich_S]

I like the idea of using an immersion chiller and pump to maintain mash temps. Do you have a temperature controller or do you monitor manually and turn the pump on and off?

 

[Northcalais40]

I actually read in a previous thread ajf's advice about stirring well to increase efficiency. This made sense to me, so I did it and did have higher efficiency. Though to be fair there are too many variables involved to show any proof. What is agreed by consensus (I think) is that there is little efficiency gained by reaching mash out temps. I certainly wouldn't invest a lot in equipment that you probably don't need. A quick decoction will bring you up to 170F in 15 minutes. The benefit, as I understand it, to reaching mash out temps, is that you get a quicker denaturing of the mash, to fix your ratio of fermentables to non- fermentables more quickly.

 

[RM-MN]

One of the major contributors to mash efficiency is the quality of the crush. If you have larger flakes or pieces it is difficult for the water to reach the center of the pieces and activate the enzymes and more difficult for the sugars created to be extracted. Ideally, you want very fine pieces but then you have trouble keeping the grain out of the boil and end up with stuck sparges as the finer pieces clog up the strainer. To avoid that situation you can increase the filter area and decrease the filter size. One way to do that is with the "Brew in a Bag" which uses a very fine cloth bag to contain the fine grain particles. You do not have to embrace the "Brew in a Bag" system in whole to achieve this, you can simply line your conventional mash tun with the fine cloth (paint strainer bag or Swisse Voile cloth) and if you seem to be getting your filter clogged, simply lift the bag of grain up to increase the filter area. You can do this for the mash out and drop the bag of grain back in to do the sparge and lift it out a second time if necessary. Give the finer crush/grind and cloth filter a try and see if your efficiency doesn't improve. I'd bet that the increase efficiency will pay for the bag withing 2 or 3 batches.

 

[mrk305]

A few years ago I used to use a pressure cooker to raise the mash temp. I just unscrewed the fitting that the jiggle weight goes on and replaced it with a 1/8 pipe thread 3/8 hose barb and let the steam bubble up through my braided hose.

I don't remember how quckly this raised the temp.

 

[DeafSmith]

I like the idea of using an immersion chiller and pump to maintain mash temps. Do you have a temperature controller or do you monitor manually and turn the pump on and off?

I don't use the coil to maintain temperature - it is only put into the mash if I need to raise the temperature. I dough in, stir, and check the temperature - if it's OK I put the lid on the tun - halfway through the mash I check the temp. again - if I have lost too much temp. I put the coil into the mash and turn on the pump for a couple of minutes, stirring and monitoring the temp manually. At the end of the mash I put the coil in for mash out, turn on the pump and stir until I reach 168º F (this takes about 10 minutes, more or less depending on mash temp. and on how much boiling water is in the kettle - the water cools off while being pumped through the coil, and a larger quantity will cool less, maintaining more heating capability).