Experienced batch spargers only

Went allgrain a year ago and I have experienced the Clint Eastwood of brewing." The Good , the Bad, and the ugly". I got “How to brew” for B-day and it has raised another question. I’ve read Denny’s and the section in HTB and John Palmer talks of mash depth as far as temperature retention, and efficiency. I use a 52 qt rubbermaid cooler and have brewed only 1 batch in the last year that the grain bill was in excess of 12 lbs. I’m contemplating building a 5 gallon mash tun, and save the 52 qt for large beers. I’d like to hear from people with experience especially if they usually are brewing double batches or high gravity beer with huge grain bills. Thanks.

I have had as much as 26# and as little as 5# in my 50qt igloo “ice cube” cooler.

I kinda hate to say it, but ignore John in this case. I use a 48 qt. cooler with grain amounts from 10 to 20+ lb. No real difference in mash tun performance. IIRC, John is talking about fly sparging, right?

No, it is for batch sparging and one of the last video’s he did on NB was batch sparge also. I know that you can get a lot of grain into a 52 qt. cooler, but are you making strictly 5 gallon batches or are you making larger batches. I make 5 gallon 1.040 to 1.056 OG batches so my usual grain bill is less than 12 lbs. This leaves alot of dead space above the mash, because of the larger surface area the grain bed is not asd deep, therefore, the larger surface are is prone to heat loss. I do preheat my mash tun with boiling water so I have recently been getting alot better at hitting my temps. I added insulation to the top so I usually don’t lose more than a degree or 2 during the mash. That being said it was the first time I saw a reference to “Grain bed depth” . A 5 gallon cooler will have a smaller interior space area,therefore, the surface area would be smaller and the grain bed deeper. He also said add it is better to add the water to the grain vs. grain to water. why I don’t know, I’m not as smart as 90 % of the people here I just want to make decent beer.Please note “Paralysis by analysis”. Thanks.

Like Denny, I use a 48qt. 52qt is only 1 more gallon. Maybe only 1" difference in depth?

Most of my beers are in the 1.050 (12lb) range. Only 1/2 of the cooler is filled.

IMO you have less chance of dough balls by adding the grain to the water. What ever works for you is the way to go. And I use my “pre heat” water as my mash water. So it would be silly to drain it, add the grains and add the water back in.

If I had to guess, a lot of the information coming from homebrew texts originated on the professional level. So references to grain bed depth and liquid flow, while vital in a pro setup (actually good info for fly sparging), do not always apply the same way to a homebrewing set up. If you are batch sparging you enough grain to get a good filter.

The “adding water to grain or grain to water” is probably only a concern if you are taking forever to add the grain to the water in a non-preheated mash tun (in which case the water might be 170*+ and then you have to worry about enzymes being denatured. I don’t think anyone has had a problem w/ it but JP probably just wanted to cover all bases.

I use a 120-qt MaxCold cooler with a wide range of grain weights and I mash on the thinner side. Sometimes the cooler is less then half full, sometimes it’s filled to the top, and IME the grain bed depth makes no difference at all to the conversion efficiency or the heat retention.

Last year I experimented with sizing down from a 70 qt cooler to a 48 qt cooler over the same concerns you expressed. I also typically brew 5 gallon recipes in the gravity range you mentioned, but bought the bigger cooler in case I wanted to brew bigger beers. In my case, what I found was that there was no appreciable difference in temperature retention and went back to my 70 qt cooler. I’ll typically lose 2-3* over the course of the mash, depending on the time of year, with a 10-15 lb grain bill (which leaves well over half of the cooler empty), and did not lose anything a few weeks ago when I mashed 26.5 lbs. for a barley wine (it was filled to capacity since I did it no-sparge).

If you’re only losing ~2* over the course of your mash, I wouldn’t be too concerned. Maybe heat your strike water so that you mash in 1* over and end 1* under and call it even? As you mentioned, I also found that pre-heating the tun helps a lot with hitting target mash temps.

I would concur with what’s been said. I have a 70 qt Coleman xtreme that I’ve filled with various grain bills ranging from 10 up to 35 lbs. I typically loose 1 degree per hour regardless of grain depth or ammount. I always preheat with 2 gallons of boiling water.

Thanks everybody I appreciate the input. Like I said the more questions I get answered the more questions I have.

Go to Home Depot and buy some of the Rigid Pink insulation that comes in sheets. It is about 1.5" thick. It took some trial and error, but I was able to rough cut two pieces to just larger that the inside of my Igloo cube cooler. I then glued them together and when they tried, I carefully shaved it down with a rasp to fit inside the walls of my cooler.

Once I mash in and am happy with my starting temp, I drop the 3" panel in, close the lid and come back in an hour. I lose a degree or two at the most.

Having tried both ways, grain to water works FAR better for me. I make 5.5 gal. batches 99% of the time. Anywhere from 10-16 lb. of grain is normal for me. I usually lose 1-2F on a 5 gal. batch. Not enough to worry about. Grain bed depth makes a difference in fly sparging, but little to no difference in batch sparging.

I typically run grain bills in the 48+lb range in my coleman xtreme and have very little temp loss. I have insulated the lid with expanding foam.

I have a 16qt MLT for 2.5-3gal batches, a 28qt MLT for 5gal batches, and a 60qt MLT for 10-15gal batches. I do like to keep them mostly full to get the most consistent mash temp. I also just bought a 100qt cooler for trying 15gal no-sparge batches. Why do I have all these? I started small and worked my way up.

I’ll echo all the other posts- heat loss doesn’t change much with cooler size. Denny states that his gear will lose 1-2 degrees over a mash. I think mine is in that neighborhood, which is fine. I think its fair to say that many of us don’t have thermometers that are even accurate enough to reliably measure a 2 degree temp loss. I consider a degree or two within the error range for measuring temps. This is a second reason to not worry about it.

I think the quality of the cooler is a bigger concern than cooler size or air space. Cheap coolers have less insulation, and lose more heat. More expensive cooler have more insulation, and hold heat better.

Perhaps I’m in the minority here but I like the round coolers from Igloo, not Rubbermaid. On the Igloo coolers the outlet is molded together between the outer and inner liner, whereas on the Rubbermaid the inner liner will actually slide out over the course of many mashes from the glue losing adhesion.

I have a 5 gal for regular and session brews, and a 10 gal for ultimate brews. I’ve easily done a 1.104 OG Barley Wine with 24lbs of grain with room to spare. Temp loss is minimal as well. I’ve measured 1 degree per hour routinely, but I’ve also insulated my lids with expanding spray foam.

Are the lids a big source of heat loss? I lose a few degrees usually and wonder if some foam might help.

Heat rises, so I think you lose the most thru the lid. Unless the walls are real thin

[quote=“tom sawyer”]Are the lids a big source of heat loss? I lose a few degrees usually and wonder if some foam might help.[/quote]Yes. My lid didn’t have any insulation, so I drilled a hole and applied the spray-in insulation. It helped a lot.