To repitch add some sugar or wait it out. That is the question.

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

MrBrown

Well-Known Member
Joined
Jan 28, 2013
Messages
79
Reaction score
7
Location
Sunrise
Brewed a BBS all grain Dry Black Stout Mix that is now 2 weeks in the fermenter.
In brewing this kit i missed the temps for the mash when i tried to hold the temps in an oven. (never doing that again) After steeping the grains for an hour at 165~169F. OG going into the fermenter was 1.036. I started rehydrating yeast about an hour before it was pitched. I boiled spring water then let it cool to room temp dumped the yeast in taking care not to dump it on itself. I let it sit for a few minutes then gave it a swirl a few times. I was a little more effecient with my ice bath and got the wort down to 64F. Room temp in my South FLA home is 72~75F. After transfering to primary and aerating with a milk frother i gave the yeast another swirl then pitched. I normally monitor the first 72hrs for fermentation activity. after 12 hours at room temp little noticable activity stopped. This was the weakest activity i have seen in the 7 batches i've brewed. I noticed some particles clinging to the side of the carboy and after a week in ther fermenter i gave it a swirl. I'm thinking i either messed up the yeast beyond rescue when i rehydrated or i missed my effeciency when i tried to keep mash temps using the oven. Maybe both?
 
1.036 is relatively low, and if you had good aeration and healthy yeast its very possible it finished up quickly. You ask if you screwed up...its possible you did very well (except for the low OG).

Take a gravity, see where it is, if you're still unsure wait another day or two and take another gravity. If it reads the same its done fermenting and you're all set.

I've had a few brews come out with low OGs like this and they turn out great. I wouldn't add any more sugar at this stage, your beer should be fine!
 
What concerns me is the high mash temp. It should've been more like 152F or so. Also,if you have a winter coat with thinsulate lining,or something similar,try wrapping the mash kettle in that, Get the mash up to the desired temp while stirring to break up dough balls & get it evenly wetted. when it's up to temp,wrap it up in the coat for the 1 hour mash.
My winter hunting coat does this so well,I acctually gain 1 degree istead of loosing a lot more. Higher mash temp generally equals less fermentables.
I'm also wondering how much water you added for total fermenter volume?
How much grain & extract did you use?
 
Have you taken a gravity reading?
I only have a refractometer and didn't want to mess with the conversions for figuring out the gravity. In lieu of all this i'll try my hand at using a calculator on here.
You ask if you screwed up...its possible you did very well (except for the low OG).
I appreciate your optimism.:mug:
how much water you added for total fermenter volume?
How much grain & extract did you use?
Outside of the water used to hydrate the yeast ~1/4 cup
no extra water was added. I think the mix is 2.5~3lbs of grain. No extract
What concerns me is the high mash temp. It should've been more like 152F or so.
I've been dabbling with different methods to hold mash temps.
So far i've tried Stovetop, mini-mash tun and the oven. Mini mash tun seems to be the winner. I'll try your coat method.
 
Yeah,if you have a well isulated coat,try wrapping the mash kettle in it. Def solved the mash temp problem for me. See if it gives better efficiency for you. combined with properly stirring the mash,of course. Thes to things should bring the OG's up.
 
In terms of helping to minimize heat loss in lieu of a coat you can also use blankets. I have a fairly large mash tun so I wrap the thing in an old bed comforter and pile an extra blanket or two on top, after an hour+ mash I may only lose a degree or two.
 
That's why I tried the thinsulate lined coat. i gained a degree instead of losing temp. But loosing only a degree or two can be compensated for & isn't too bad. My concern was that this is where his low OG problem cones from.
 
I checked the gravity last night
OG 9.4 Brix
FG 3.6 Brix
When i plug it into the claculator on seanterrill.com i get 4%ABV
I tasted a drop and it wasn't too bad.
i'm not sure what the recipe calls for the ABV to be.
 
What does the brix convert to? I know those refractometers measure in brix & must use conversion formulas to get regular gravity numbers after fermentation starts.
 
FG is def too low. Low mash temps generally make for more fermentables. For darker beers,it seems to me a higher mash temp would be better,like 154-155F. That should raise the FG a little.
 
Keep in mind your gravity will be off using a refract once alcohol is present. So that might not be accurate at all.
 
I'm curious about your temps and the oven:

you stated that you mashed and steeped. The high 160 degree temps would indicate "steeping" which is normally associated with extract and partial mash brewing instead of all grain. Mashing would normally be done in the 145 to high 150's temp range where the conversion process is more efficient. The inefficient conversion of starch to sugar of steeping (the high 160 degree temps you stated) would explain the lower than expected gravity. You probably know all this...but the difference is significant.

I have found the oven to be very good at holding mash temps, especially for batch sizes less than 5 gallons. The key to any mashing method is "holding" temps, which means using a mash calculator to get the starting temp right. Once you hit the starting temp physics takes over...simply a matter of minimizing heat loss. Contrary to the thinsulite claims above....unless you add more heat the temp can't increase no matter how well you insulate(the thermometer reading might change). Physics dictate that you have 3 choices to "hold" mash temp: 1) add heat to balance heat loss...very hard to do without proper equipment 2) minimize the temp difference between the mash and the surrounding environment ie. oven set at or near mash temp 3) attempt to insulate the mash to slow the heat loss to the surrounding environment.
Great information and techniques for method 2 and 3 are available in Deathbrewer's excellent threads on partial mash brewing.
 
I'm curious about your temps and the oven:

you stated that you mashed and steeped. The high 160 degree temps would indicate "steeping" which is normally associated with extract and partial mash brewing instead of all grain. Mashing would normally be done in the 145 to high 150's temp range where the conversion process is more efficient. The inefficient conversion of starch to sugar of steeping (the high 160 degree temps you stated) would explain the lower than expected gravity. You probably know all this...but the difference is significant.

I have found the oven to be very good at holding mash temps, especially for batch sizes less than 5 gallons. The key to any mashing method is "holding" temps, which means using a mash calculator to get the starting temp right. Once you hit the starting temp physics takes over...simply a matter of minimizing heat loss. Contrary to the thinsulite claims above....unless you add more heat the temp can't increase no matter how well you insulate(the thermometer reading might change). Physics dictate that you have 3 choices to "hold" mash temp: 1) add heat to balance heat loss...very hard to do without proper equipment 2) minimize the temp difference between the mash and the surrounding environment ie. oven set at or near mash temp 3) attempt to insulate the mash to slow the heat loss to the surrounding environment.
Great information and techniques for method 2 and 3 are available in Deathbrewer's excellent threads on partial mash brewing.

Contrary to your thoughts,I've done it twice already. the coat in question has this poofy,airy material surrounding the thinsulate used in it's construction,& wasn't cheap at Gander Mountain where I bought it. This airy material helps trap air,which is a very good insulator.
I also use a floating thermometer in the BK/MT when mashing 5lbs of grains in 2 gallons of water. Twice now I've measured a 1 degree rise in temps. What I did was heat the mash water with the paint strainer bag in it to 150F. Then quickly stir in the grains,break it up,etc till wanted mash temp is reached. I have the coat laid open on the island behind me,with two pot holders layered inside the opencoat back. Place the kettle on them covered,hood over top of kettle. Sides wrapped around that with the sleeves tied once around all that. 1 hour later,unwrapped it & noted 1 degree rise in temp,removed lid & a lot of steam rose out of it. So it did work as noted...
 
Keep in mind your gravity will be off using a refract once alcohol is present. So that might not be accurate at all.
Right. This beer isn't 1.001 for a FG.

9.1 brix measured before fermentation
3.6 brix measured during/end fermentation
I've plugged these numbers into a few different calculators and get back 1.001~1.002 for FG. It's my first Refractometer attempt so it wouldn't suprise me if i've messed up somewhere. (again)
 
9.1 brix measured before fermentation
3.6 brix measured during/end fermentation
I've plugged these numbers into a few different calculators and get back 1.001~1.002 for FG. It's my first Refractometer attempt so it wouldn't suprise me if i've messed up somewhere. (again)

The calculator is wrong. It's that simple.

Once alcohol is in the mix, the light refracts differently.

Try it yourself! Sanitize the hydrometer, the hydrometer tube, and a turkey baster and take a hydrometer reading. (You can put the sample back in the carboy, if you sanitize well enough).

See what the reading is.

I feel that even though the OG was low, that with such a high mash temp the beer should not finish anywhere under 1.014 unless it's infected or your mash temp was wrong. And 1.001 is a terribly low FG, even for a beer that didn't have problems in the mash.
 
My guess is that there are two sources for the extra heat unionrdr is seeing. 1) the metal burner the pot is sitting on, 2) the metal pot the mash is sitting in. If either of those is substantially hotter than your mash temp, heat transfer from them into the mash can continue raising your mash temp after the burner is shut off. I've seen this phenomenon too - mostly in an irksome overshooting my mash temp by a couple degrees way... and I use the wrap the pot in lots of blankets method on top of the stove, I like mashing at 154F and after an hour I'm at 151-152F.
 
My guess is that there are two sources for the extra heat unionrdr is seeing. 1) the metal burner the pot is sitting on, 2) the metal pot the mash is sitting in. If either of those is substantially hotter than your mash temp, heat transfer from them into the mash can continue raising your mash temp after the burner is shut off. I've seen this phenomenon too - mostly in an irksome overshooting my mash temp by a couple degrees way... and I use the wrap the pot in lots of blankets method on top of the stove, I like mashing at 154F and after an hour I'm at 151-152F.

I had too much trouble with trying to control mash temps on the stove with the new burners (electric). The old ones took too long to get to a boil,but held temp well. The new ones heat up really fast,but don't hold temp worth a darn. so I wrap it in my thinsulate lined winter hunting coat. Like I said before,it has this light,airy material surrounding the thinsulate,which holds air. Air being a great insulator,the temp somehow goes up that one degree. but off the stove completely. I don't ask why,I just know it works. Close enough for me!:rockin:
 
The calculator is wrong. It's that simple.

Once alcohol is in the mix, the light refracts differently.

Try it yourself! Sanitize the hydrometer, the hydrometer tube, and a turkey baster and take a hydrometer reading. (You can put the sample back in the carboy, if you sanitize well enough).

See what the reading is.
.

He's plugging the final refractometer reading into a conversion calculator that takes alcohol into effect.

Read into it here: http://seanterrill.com/2011/04/07/refractometer-fg-results/

And the calculator is here: http://seanterrill.com/2012/01/06/refractometer-calculator/
 
I had too much trouble with trying to control mash temps on the stove with the new burners (electric). The old ones took too long to get to a boil,but held temp well. The new ones heat up really fast,but don't hold temp worth a darn. so I wrap it in my thinsulate lined winter hunting coat. Like I said before,it has this light,airy material surrounding the thinsulate,which holds air. Air being a great insulator,the temp somehow goes up that one degree. but off the stove completely. I don't ask why,I just know it works. Close enough for me!:rockin:

yes, I have no doubt the thermometer reading goes up for some reason...but even perfect insulation won't increase the temp. The extra heat is either added somehow....or the reading simply shows slightly higher due to mixing or stratification. No matter what is happening it sounds like you have a nice stable mash process.
 
Yeah,I'm happy with how it's finally getting stabilized. My BK/MT is 5 gallon SS. With the amount of grain/water in there,& the fact that it's pretty steamy when opened tells me the steam may be influencing the reading somewhat. But at least it's stable & works real well. And that's what we're all shooting for.
 
I am also confused about the process, Mashing and steeping are very different processes requiring very different temperatures.

I have used my oven to great success in controlling my mash -put the pot in the oven, heat the oven to just under mash temperature (it may continue to rise from the hot elements) then turn it off. It holds to within 1-2 degrees. I do not try to adjust during the mash.

Make sure the 1.001 measurement is taking the alcohol into consideration. If not just ignore it. You will have beer. If it is truly at 1.001 it might be a bit dryer than anticipated but still beer.
 
He's plugging the final refractometer reading into a conversion calculator that takes alcohol into effect.

Read into it here: http://seanterrill.com/2011/04/07/refractometer-fg-results/

And the calculator is here: http://seanterrill.com/2012/01/06/refractometer-calculator/

I've never had an accurate reading with those calculators, especially when the Fg is so suspect- 1.001 with a mash temp of 160? Not likely, but possible if there is an infection or another issue with the mash.

For my refractometer, the calculators come close sometimes, but never really accurate and certainly not enough to rely on them when the FG they provide is suspect.
 
Back
Top