Experienced BIABer, new to all grain mash tun having trouble being consistent and low efficiency

[Jbrew]

So, I began my homebrewing as a BIAB brewer. Manage to become pretty comfortable and consistent in getting my temps and efficiency fairly quickly. More recently I was looking to replace my brew kettle that I damaged putting in a ball valve previously and found another homebrewer selling an anvil brew kettle with burner, mashtun, CFC, and a few other misc things. So i jumped on the deal and was excited to try using a mash tun. Well I just cant seem to hit my temps properly, i keep ending up too low and my efficiency is about 45%. The first time I didn't realize that the mash tun needed to be preheated. So the second time, i filled the mash tun with hot water directly from my faucet. Water temp from my hot faucet is approximately 150. Thought this would at least get me pretty close to preheating the mash tun, but still ended up too low by about 6 degrees.
So my questions are:
1. I know low mash temps generally create a more fermentable wort, where higher temps do not, does this affect the gravity? Or does it affect whether the sugars are fermentable?

2. Sparging rinses the sugars from the grain correct? How fast or slow should I be sparging? I've read generally sparging can take an hour.

3. I have a little tan 12v pump I use to recirc for the first few minutes just to try and stabilize the temperature in the mash tun. I don't do it too long because I know it will cause some heat loss. Am I doing more harm then good here?

And

4. What effect does grain to water ratio have on the mash and efficiency? I know 1.25 - 1.5 qt/pound is the general rule, but larger volumes should help keep the temp more stable correct?

Thank you guys for any help, i know this post is long winded. I apologize if this has been answered before.

 

[Sammy86]

So my questions are:
1. I know low mash temps generally create a more fermentable wort, where higher temps do not, does this affect the gravity? Or does it affect whether the sugars are fermentable?

2. Sparging rinses the sugars from the grain correct? How fast or slow should I be sparging? I've read generally sparging can take an hour.

3. I have a little tan 12v pump I use to recirc for the first few minutes just to try and stabilize the temperature in the mash tun. I don't do it too long because I know it will cause some heat loss. Am I doing more harm then good here?

And

4. What effect does grain to water ratio have on the mash and efficiency? I know 1.25 - 1.5 qt/pound is the general rule, but larger volumes should help keep the temp more stable correct?

1. From what I’ve read and understand the temp of the mash affects FG...so your beer will be drier at lower FG’s.

2. Yes, sparging rinses the remaining sugar from the grains...there are two types of sparging Batch and Fly. Batch sparging is used when you drain the mash tun completely and then you dump all the water you will need to get to your pre-boil volume into the tub in one shot to rinse the sugars. Fly Sparging is where you drain the mash tun slowly and add water at a consistent rate leaving about 1-2 inches of water above the grain to rinse the sugars. This method generally takes longer anywhere from 30-90 minutes depending on flow rate.

3. The problem I see with you recirculating is you’re losing heat while recirculating because you don’t have a hot liquor tank with a HERMS coil to help keep/stabilize temperature. If your HLT had a HERMS cool recirculating wouldn’t be an issue but since you don’t you are definitely losing temperature.

4. I really can’t speak to the science behind the water to grain ratio with any certainty. I know I generally keep the ratio 1.5/pound for ales and 1.25/pound for lagers...I didn’t do it intentionally at first Beersmith made me do it and I’ve kept it that way since.

Hope this info helps you on your brewing journey and good luck!

 

[eric19312]

I’d like to review your strike water temp calculation. With brewing in an ice chest you normally look to land right on your temperature. You are way too far off something is not right.

I need to know
Weight of grain
Temperature of grain
Volume of mash water
Desired mash tem
Calculated strike water temperature

I’ll compare to calculators I use and am sure we will see the problem.

As for the recirc pump...I’d not use it unless you build a RIMS or HERMS. Just stir that grain in good when you dough in and give it another stir about half way through the mash. Otherwise keep the cooler closed tight to keep in the heat.

 

[Jbrew]

I use the brewers friend strike water temp calculator. It does not take into account preheating the mash tun. It only tells me what temp for how much water/grain ratio based on grain temp. It can be found here:

It has always been fairly accurate before when doing BIAB, but full volume would be much more stable, and there's no preheating as im mashing in the kettle which was used to heat the water obviously.

Admittedly I never measured my grain temp, and always left the default at 65. But where my bag of grains are stored is in a cabinet about mid wall height and I can say that they definitely shouldnt be colder then that. That said, I will now measure my grain next time just for the purpose of being sure. Also, I am using a k type thermocouple thermometer with 2 probes. The probes read within a degree of each other, however I have not determined the accuracy of it since I bought it. I also have a thru wall thermometer on my BK, but again i bought the kettle used, so I'm not certain of that thermometer accuracy either. I am using the BK thermometer for strike temp and I recirc the water while heating strike temp thru the whirlpool port to try and keep temps consistent thru the kettle. I know i could just stir, but been wanting to have fun using the little pump. I drop both thermocouple probes in the mash and I do stir when mashing in. I also underlet the grain by filling the mash tun with water thru the ball valve, rather then adding grain to water. I am using a brew bag in the mash tun rather then a false bottom or screen, i do have an elbow installed in the ball valve to keep the bag from clogging the valve. All this is in a lowes 10 gallon igloo cooler. I let mash for the full 60 minutes every time. I then "vorlauf" with the tan pump. Ive learned that this is not really necessary, but again, me just playing with the pump again. I then batch sparge, again with the pump, throttled with a ball valve on the output, im guessing this maybe the cause of my low efficiency. I've been doing it this way as I don't really want to put my BK on the floor to run off the mash tun and then have to lift the BK with the full volume. My main reason for the pump was to run the CFC, but also to try and minimize lifting 6-7 gallons of wort. This current recipe also called for a Mash out at 168. To accomplish this, after the first batch sparge I had my first running in the BK, and my next batch of sparge water in the mash tun. I then used 2 tan pumps, one at the ball valve on the mash tun, and one at the ball valve on the brew kettle. The BK pump pumped to the mash tun and the mash tun pump pumped to the BK whirlpool to create a circuit. I then fired up the burner on the brew kettle and began the circulation between BK and mash tun I guess kinda like a crude herms system without the heat exchanger coil. It took about 10 minutes of circulation to get to the correct mash out temp, at which point i then turned off the pumps and let it sit another 10 minutes as the recipe calls for. So that's my process. I apologize as I'm sure there's a butt load of variables and way overcomplicated with the pumps. I'm sure I'm really the reason this isn't working. I'm just looking to have fun a little with some machinery while doing it.

Now here's the specifics to the recipe that I last did:
Recipe is:
OG 1.043, 75% efficiency
5.5 gallons post boil volume
8.5 lbs of grain,
4 lbs red wheat, 3.5 lbs mesquite smoked malt, 1 lb carapils.
Mash 60 minutes at 152
Mash out 168 for 10 minutes

I used approximately 150 degree water and filled the mash tun halfway and let it sit for about 10 minutes in an attempt to try to preheat the tun. Then drained. My strike temp according to the calculator should be at 160.7 for 2qts/pound of grain. Used 2qts/lb in hopes that it would be a little more stable about keeping temps rather then 1.25 or 1.5qt/lb. Put my brew bag in with grains, and closed up the tun and then underlet my strike water thru the ball valve. Once my strike water volume is in, i then open the tun back up, stir well, drop my thermocouple probes in about approximately middle of the grain bed and close back up. Right away I look at my temps and see that they are at 146. I then use the pump to recirc to try and make sure the the temp is consistent. I only do this for about a minute or 2 as I know recirculating without heating will cause heat loss. Temps still hover around 146.
At this point I just let it go because I'm not sure how much of what temp water to add since my strike temp calculator was off to begin with. My temps stay pretty consistent throughout the 60 minutes though. As stated by the recipe, i do the mash out during my batch sparge and runoff to the BK. I use the 1/2 qt to one pound rule for grain absorption, but for some reason on this mash, i ended up with 8 gallons of pre boil wort. Doh! I usually shoot for 7 to end up with 6 gallons post boil leaving 5.5 after fermentation so i can keg 5 gallons and usually get about a 6 pack bottled.
So once i have my pre boil volume I then take a hydrometer reading. I get 1.018
Even at 8 gallons with the 8.5 pounds of grain that I'm using, I should get 1.029 at 75% efficiency. I got about 45% efficiency according to the calculator. I know this post is really long. I do apologize, but I appreciate your willingness to help and i wanted to give the whole picture of the process. I'm sure I'm way over complicating things and causing my own problems. At this point I can live with the low efficiency, if I could just consistently get my temps correct.
Thank you again very much for any advice.

 

[Lefou]

A more fermentable wort simply means there's a larger amount of simple sugars (like fructose and glucose) in solution compared to the complex sugars, dissolved proteins, and carbs. This wort will attenuate better and will yield a drier result. Two different worts can have the same specific gravity but give different attenuation levels based on their differing sugar constituents.
This is one reason why people get confused about beer colors and act surprised how the Germans could brew a dark lager and those Belgian monks could make heavy, kick-@$$ triples and golden ales.

Double check and make sure your thermometers are good. Your issue is why I basically retired the Igloo cooler and modified my Anvil kettle with a false bottom for step mashing.

 

[RM-MN]

Low mash temps could give you lower OG if you are so low that conversion cannot complete. Here's a nice article about Brewers Window and how the temperature affects conversion and fermentability.

https://missionarybrewer.wordpress....ers-window-what-temperature-should-i-mash-at/

If your mash was within the Brewer's Window, your lack of conversion was mostly due to the crush of the grain.

Fly sparging should be done slowly so you don't get channeling in the grain bed. Batch sparging is quick, dump, stir, drain, repeat. Unless you like to spend time babysitting the sparge there is little to be gained by doing a fly sparge.

There is not real need to recirculate. Even a stirring doesn't help much. Leave the mash tun closed until mash is done.

Grain to water ratio has to do mostly with how thick you can stir and how much water you want to leave out to use for sparging. I've done some incredibly loose mashes and got great (and quick) conversion.

 

[Hwk-I-St8]

First, do a batch sparge and don't worry about a mash out. With the speed of a batch sparge, it's not necessary. I usually use 170 degee water for my sparge water and just dump it in, stir like heck for a few minutes and then drain. I use a hoist for my bag to help it drain and do a mild squeeze on the bag. With a fine crush, I'm hitting 70% pretty consistently.

Second, I'm finding your strike temp issue to be very strange. You're using the same thermometer to measure the strike water temp as you're using for the mash? I typically do about 1.5 quarts/pound mash thickness and my strike temp is usually around 163 for a 152 degree mash temp. I can nail that pretty consistently and that's using 125 degree tap water to pre-heat the MLT. With 2 quarts/pound, I would not expect to see a 14 degree drop when adding grains. Short of potential disparity between therms used (if they're not the same), I really can't answer the strike temp issue. One other possibility, I guess, is if the temp is dropping between the kettle where it's heated and before it reaches ball valve on the cooler. I usually heat just slightly above my strike temp, transfer to the cooler and let it cool to precisely my strike temp before adding grains. I've wanted to try underletting, but haven't because of a concern about not hitting my mash temps due to less control of the water temp going into the MLT. I use brew365.com to calculate my strike temps and I'm within a degree every time.

I would not bother with any sort of recirculation if you're mashing in a cooler. It can be done by using a hot liquor tank and coil that you run the mash through, but I don't see the point. I do a bag in a cooler and hit about 70% (+/- 1) consistently with my typical grain bill. Playing with the pump is fun, but brewing great beer is more fun.

Finally, I'd get your mash temp issue resolved and see if the efficiency issue goes away with it. I'm not an expert on what happens when your at the edge of the typical mash temp window, but if it were me, I wouldn't be diagnosing mash efficiency when I'm missing my mash temps so badly.

In general, simplify the process first: skip the underletting, absolutely make sure temps are accurate for strike and mash, do a simple, easy batch sparge and drop any attempts to recirculate or mash out.

Oh, one other thing: with the batch sparge, try to get equal first and second runnings and take gravity readings from both. It will help you diagnose where there are issues.

 

[eric19312]

Thanks for the detail. I like your strategy for getting to the mash out temp via a circuit to the boil kettle. Nice idea I'd continue to work on that idea after you get your mash temp issue sorted out. Not suggesting this as a long term solution but next time you are shooting for 152 and your cooler mash tun has stabilized at 146 why not start that recirc loop and heat up your mash. Use a low flame at the BK you don't want to overheat the circulating mash. I basically do this in my mash which is a direct fire kettle with a false bottom. Recirc through the whole mash and fire the burner based on temperature of the recirculating wort.

But I digress and you should be able to get much closer to your strike temperature in a cooler mash. My guess is measurement accuracy. You already raised possibility of thermometer calibration and measurement of grain temp. Those are worth checking. Maybe you were really at 152 all along. The other things you measured were volume of strike water. How accurate was that measurement? Any possibility you used less water than the calculator called for? Finally you measured the grain weight. I doubt that is the issue as it would take more grain than recipe to have too low mash temp and that would not match your low efficiency issue but still I'd review each of your measurements for accuracy.

 

[brewcat]

The problem with the brewersfriend calculator is you can't adjust for equipment loss. I just account for 5 degrees of equipment loss and don't mess with preheating.

 

[Jbrew]

Thanks everyone. Sorry about not replying for a while.
I do not use the same thermometer for strike temps that I do for the mash tun. The mash tun i use a dual probe k type thermocouple, with both probes dropped in the tun. For strike temps I use the kettle thermometer. Agreed that maybe my temps were right on, but my efficiency still came up very low. That's why I think the temps are fairly accurate. According to the above posted link, it looks like at 146 I'm out of the window for conversion. I would think the the wort was mixed pretty well since recirculating, when i took my hydrometer reading. How accurate are hydrometers? Ive been meaning to get a refractometer anyway. As for coming up a gallon extra in volume after mashing, I'm not sure what happened there. I started with 17 quarts which is 4 gallons and 1 qt. For my strike volume. I then used another 4 gallons for mash out. With grain absorption at 1/2qt per pound of grain and 8.5 lbs of grain, I figured that should be an absorption of just over a gallon, leaving me with about 7 gallons pre boil I'm using my kettle wall markings to measure my volumes. I do not actually weigh my grain. I don't buy in bulk yet, as I don't have a mill yet. For now, i get grain bills made specifically for each recipe, so the grain bill should have been what I asked for, that is unless the brew shop shorted me grain. The grain was double crushed, for use with the brew bag.
I've read that some just fill the mash tun with 175 degree water in their required mash volume and wait till it comes down to strike temp. I may go this route, but I would like to learn how to get it right without waiting for temps so i can learn my system. I will probably can the underletting and go back to adding grain to the water.
Eric19312, I may continue to use the heat the boil kettle and pump the mash as a circuit technique for mash outs if you think its suitable for that. Would you think there's any benefit to doing it this way?
Thanks again everyone.