Category Archives: Water

Mash Tun Insulation Comparisons

It is a hard truth that you will lose some temperature during your mash.  In my desire to go electric, I recently purchased the BREWER’S EDGE® MASH & BOIL from William’s Brewing.  Without actually even having brewed a batch of beer on it yet, I already got to work figuring out how to insulate it.  I tested various insulation methods on the Mash & Boil, but the relative comparisons should be valid on any mash tun.  A post with a better review of the Mash & Boil and my reasoning for wanting to go electric will come at a later date.

Nerd Alert!

Warning, the material in this post could get a bit nerdy.


Difficulty: level_5

Easy for you

Time Required:

Just a read for you fortunately.  It took me about a week to perform the experiments.


One of the advantages of an electric brewing system should be accurate temperature control.  With such a new system as the BREWER’S EDGE® MASH & BOIL, there is a lot of discussion about the 6 degree swing in temperature control.  This is pretty well contrasted with much more expensive systems as the Grainfather or PicoBrew Zymatic that may hold temperature within a degree or two.
While I do agree this could and should be safely regulated to a tighter temperature band on the Mash & Boil, I would at least propose that the first line of defense is just to insulate your mash tun so that accurate temperature control is not as critical.  In all reality, this is a turn-key electric brewing system for less than 1/3 the cost of the other systems on the market.
I initially started brewing with a 44 Qt kettle doing 5 gallon batches with a propane burner.  I did notice a decent amount of temperature loss, so I created a thermal wrap to use during the mash.  This was made using some cotton based insulation meant for water heaters.  I did not want to mess with fiberglass based insulation.  When I moved to a 62 Qt kettle and larger batches, I think the larger thermal mass helped maintain temperatures better, but I went ahead and used the same wrap anyway.
With the new system, it had such a different diameter to height ratio, I decided to start from new again.  Since we homebrewers are a thrifty bunch, it usually comes down to whatever we had on hand at the time we needed to create it.  This time for me, however, I had enough time to plan it out and (gasp) actually test it before using it.  As stated before, these results should be applicable to any mash tun that adheres to the laws of thermodynamics.

Insulation methods to test:

Baseline – Stock BREWER’S EDGE® MASH & BOIL kettle

  1. Described as double wall stainless construction
  2. Pros: you don’t have do do anything
  3. Cons: Hypothesis is that this will be the worst performer

Duck brand, cotton enhanced (Non-fiberglass)

  1. Was about $20 when I originally bought it and that is about the going rate at your local hardware store
  2. This was the insulation wrap from my 62Q Bayou Classic kettle
  3. Pros: Fairly inexpensive, relatively easy to find and no special handing required
  4. Cons: A bit dusty when cutting and not as tidy as the Reflectix


      1. It cost me $27 for a 25 foot roll at my local hardware store and is enough for 2 kettles worth
      2. 3 layers from the lip of the kettle to the top of the control box
      3. 3 layers loosely fit on the lid
      4. Pros: Easy to work with, clean look
      5. Cons: Really requires a semi-custom fit for it to perform well
      6. I’ll have a future post with cut dimensions so you can make your own

Cold weather sleeping bag

    1. No link, as these have been in my family for a LONG time
    2. Pros: super quick and most people have them on hand
    3. Cons: If you somehow damage it for brewing, you’ll probably get in trouble with your family

Baseline – Stock BREWER’S EDGE® MASH & BOIL kettle:

Nothing to see here… move along…

Duck brand, cotton enhanced:

 This was the setup from my 62 Qt. Kettle and wasn’t a custom fit for the Mash & Boil.  I wrapped a bungee cord around it to keep it in place.


I custom tailored this wrap in 3 layers to fit this kettle.  I wanted to be sure it did a sufficient job of insulating before I finished the edges off with Reflectix tape, hence the reason for the blue painters tape.

Sleeping Bag:

I wrapped the sleeping bag all the way around the kettle once and then had enough length left over to do a sort of “comb over” on the top of it.  I finished it off by holding it on with the bungee cord.

Other methods considered (since I have seen them used), but not tested

  1. Fiberglass water heater insulation (I don’t want fiberglass anywhere near my beer)
  2. Single and double layers of Reflectix to understand the impact
  3. Custom molded expanding foam mold
  4. Red-Hooded sweatshirt

Setup and Test Methodology:

I have not modified the Mash & Boil in any way.  I just used the unit in stock condition and let the temperature controller do it’s thing to get the water up to temperature.  I used exactly 6 gallons of RO water for the experiment.
The kettle was placed in my basement storage room, which maintained a consistent 65 degF throughout the testing.
I had 3 temperature probes in the kettle.  One at 1″ from the bottom, then another 6″ up and another 12″ up.  This was a nice spread for 6 gallons of water.  In reporting temperatures in this experiment  I am only using the temperature sensor at the 6″ height.  The other sensors were a proof of concept for some future testing I plan to carry out.  I did see some stratification in the temperatures over time as the water cooled, but for consistency, I chose the 6″ probe.
To start the each test, I topped off to 6 gallons and set the Mash & Boil to 215 degF and let it ramp up.  As soon as the system was boiling, I turned it off and unplugged it from the wall.  Temperature measurements were taken approximately every minute.  I allowed the temperatures to cool to somewhere around 100 degF or as long as I could stand it.  Absolutely no stirring or opening of the lid occurred during the cool down.
The critical stage in the test was when the water cooled to 155 degF.  At that point, marker would be taken and then compared to the temperature exactly 60 minutes later.  This would be indicative of a typical mash temperature and the relative temperature loss during the mash.  Yes there will be different thermal capacities of a water/grist mix, so to reduce the experiment to just the insulation, straight RO water was used.


I normalized the cool down datasets so that the start time (t=0) was the same for each configuration at 200 degF.  As a visual reference aid, I placed a line at 155 degF to see what the curves look like near mash temperatures.  One can clearly see here that the baseline configuration with no additional insulation decreases in temperature the most rapidly.  The cotton based insulation is a bit better, then beat by the Reflectix and then the sleeping bag.
024-Mash Tun Insulation - Cooling
This small table places numerical values on the temperature drops through a simulated mash temperature window.  I calculated these temperature drops by taking the very last data point that was greater than 155 degF.  Then I grabbed the next data point that was +60 minutes from that initial point.  The values shown are then the differences between those two temperatures.
024-Mash Tun Insulation - Results Table
To glean even more from the data, I plotted the 4 different configurations only through the mash temperature window.  I normalized these curves so that the start time (t=0) was the same for each configuration at 155 degF The left axis shows the actual temperature reading, while the right axis shows the temperature drop, relative to the 155 degF starting reference temperature.  I also placed a helper line at 155 degF.
If you are to accept the belief that most of the conversion is done within the first 15 minutes of the mash, both the Reflectix and Sleeping Bag insulation methods show a drop of less than 1 degF within the first 15 minutes.
024-Mash Tun Insulation - Mash


My worst fear when starting this experiment would be that there would be little to no measurable difference in the insulation methods.  I was pleasantly surprised when processing the results, there were clear and measurable trends in the data.
None of the installations were optimized, but I think that unless you are really a stickler, the level of care i took on each installation is all the typical brewer would want to mess with on brew day.
Even though the clear winner in this showdown was the sleeping bag, as with almost all of my brewing equipment, I prefer to have it all dedicated to just brewing.  As such, I will go with the Reflectix jacket.  I am not going to pull the sleeping bags out of our closet on brew day.  Not to mention the eventual spillage of wet sticky grain outside of the kettle and the associated clean up of the sleeping bag.  I do plan to finish off the edges of my Reflectix setup so that when it does get messy, I can just spray it off with water.
I could possibly run another test with more layers of Reflectix, and I would suspect you would get closer to the performance of the sleeping bag.  However, in my case, I purchased a 25 foot roll and intend to make 2 sets worth out of the one roll, which gave me 3 layers worth for each.


Everyone has their own selection criteria when choosing the best equipment for their needs, so I hope you’ll find the information reported in this post useful.


William’s Brewing has been set up as an affiliate site, so clicking on links to the Mash and Boil system on this site and in this post will give credit to for the referral.  This post and any others, should not be taken as an endorsement of the BREWER’S EDGE® MASH & BOIL, it was simply the test bed for my experiments.  If you found this post helpful and do wish to purchase the BREWER’S EDGE® MASH & BOIL, please click on the links listed on this site and in this post.

Water, huh! What is it good for?

Water, huh!  What is it good for?

Difficulty: level_1

Time Required:

As long as it takes you to read this post.


Back in November, I had the opportunity to see John Palmer give a seminar on water at Great Fermentations.  He was essentially on tour to promote his new book he co-authored with Colin Kaminski simply called, Water.  So the day I went to the seminar, there were tornado warnings.  As I write this, all water outside is in the form of ice.  Hopefully we’re at the tail end of the “Polar Vortex”.  A theme of things spinning, kind of like your head when you learn about water.

This isn’t a review of the book, or an in depth look at the chemistry of water, but just some of my musings on the importance of water in brewing.  Water has to be one of the most intimidating, mysterious, confusing and scientific parts of brewing.  To the beginning brewer, learning about it could confuse them enough that they think they’ll never brew good beer.

As you would imagine, at the start of his presentation I was completely engaged in what he was saying.  He had some entertaining slides correlating Lego superheros to certain elements of water.  I was understanding what he was throwing down.  I saw some charts and graphs that I understood, as any self-respecting engineer should.  Then we got to the chemistry balancing equations.  That’s when my eyes start to gloss over.  I’m reminded of the time in college when my wife (then girlfriend) said to me”your math is hard, it has letters”.  She was with me at the seminar and was following for a while and then got lost.  I never really enjoyed chemical formulas and electron counting and balancing equations.


So is understanding water necessary?  Yes!
Is being a amateur chemist a requirement?  No!
Is there an in-between that will get me producing good beer with minimal knowledge?  Yes!

First order of business is to simplify the intimidation out of the whole water thing.

In my opinion, this should be your priority level as you progress.

Starting out (Extract recipes):

Just go with tap water or water from the grocery store (see note at the end of this section).  I always went with Ice Mountain spring water, simply because I could actually taste a difference in waters and I liked it the best.  During this stage, I was always on the hunt for the water to go on sale.  For some reason, the online ads for my local grocery stores would not mention when it was on sale, nor were the sales on water the same at each location.  My benchmark price was $1/gallon, so if I saw it for that price, I was essentially clearing the shelves like some mad extreme couponer.  When I was really lucky, I would find the 2.5 gallon containers on sale and reduce the amount of plastic I was discarding each brew session.  I’ve never used just straight tap water, but I’ve tasted beers from people who’ve made beer with unadulterated city tap water and never had any complaints.  DO NOT however use softened water.

At this stage, don’t worry about treating the water.  Just brew and try to work on all of your other techniques.

*Recent reading/listening I have been doing indicates that with extract brewing, you might actually be better off with reverse osmosis (RO) or distilled water.  The theory is that the maltster making the extract has already created the proper water profile.  When the extract is concentrated, the water goes away, but the minerals are still there, so when you are adding it to your water, you are then getting those minerals in your brewing water.  This is backed up in a recent BeerSmith podcast with Colin Kaminsky and John Palmer.

Beer Brewing Water with John Palmer and Colin Kaminski – BeerSmith Podcast #70

Intermediate (Extract with steeping grains or all-grain):

This is where you want, at minimum, some sort of pH adjustment.  I use and recommend food-grade phosphoric acid.  Your LHBS should have it available, typically in 75-85% strength (ie 75% acid, 25% water).  I get it in a 4 fl.oz. container, which at an average of approximately 1 tsp per 5 gallon batch, it is good for about 24 batches.  FYI, I’m still learning and tuning my adjustments.  The much maligned colorpfast strips should suit you just fine at this stage.  Unless you just want to spring for the electronic pH meter.  As much as I love the gadgets, I opted for the strips first and have only recently purchased a pH meter.

Some details that emerged as I got more into water adjustments:

  1. Yes the colorphast strips are off by some amount (reports up to 0.3 pH) and the judging of color feels like you are being subjective, but they served me well and in my experience are very close to the digital pH meter.
  2. The most accepted method is to measure the pH of the mash about 20 minutes after dough-in, but remarkably, the amount of acid I was adding was within some small percentage of what I was adding when I was (incorrectly) measuring pH with the room temp water before heating up to strike temp.  Oh, well. Dumb luck, considering I now know that your malt bill works in conjunction with the water chemistry to alter pH.
  3. I am currently into evaluating different water chemistry spreadsheets to see which ones are most accurate at prediction.  Some of them say if you don’t know the pH of your water, just assume a pH of 8.  I got a fancy electronic pH meter to tell me that my water was 7.95.
  4. Oh, get a small sample of the mash water and cool it down before you measure the mash pH.  Unless you are using the strips, which in my usage, seem unaffected by temperature.


This is where you will be making changes that only people beyond your friends and family will notice the difference.  I’m talking about beer judges and those with the refined tastes.  I once heard Gordon Strong say on a podcast about water that water chemistry is the difference between a 30 and a 40 in competitions.  I do not feel I am at this stage yet, but what I keep telling myself is that pH adjustment alone is 75% of what matters in water adjustment.  In another podcast Jamil Zainasheff made a comment that after all of his work in understanding water, he was unsure which component of water adjustment was the most effective and wondered if it was mostly the pH adjustment.  If you do get to this stage, salts and other water additions are necessary to eek the last bit of perfection out of your recipes and really highlight your ingredients.


To paraphrase something John Palmer said at the water seminar: Just like how salt, pepper and other spices really bring out the flavor in foods, the same can be said about the additions and adjustments to brewing water.

I am currently experimenting with the various software spreadsheets available to add the theoretical adjustment ingredients and be done with it.  I’m hopeful this is doable and I will be checking back in with this theory at some point.  Of course you still want to measure again to make sure your additions had the intended effect, but it would be nice to have a predictable method.  In the BeerSmith podcast referenced above, Colin Kaminski even notes that he has it down well enough that he’ll make the adjustments to the water before hand and knows what to expect.  If it doesn’t turn out like he preferred, he brews again and essentially renames the alternate batch as a different beer.

I’ll go over water reports, filtering, measuring and adjusting water and review various software tools used to predict adjustments in future posts.

006-Water - Me and John

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