ferment on the grain. sg 1.02 but beer dry

[noobshine]

I guess this could have gone in 1st forum, or novice forum, but this was my 1st ferment on the grain so imma put it here.

my grain bill (AG... at least that was my plan)
4 lbs malted rye
4 lbs 6 row malted barley
2 lbs non-malted cracked barley

4 gallons water brought up to 160 strike temp. poured water into igloo cooler, added my grain, and 1 tsp gypsum. temp came down to about 150 which is what I was shooting for. stirred every 20 min or so for about 3 hrs. let it sit to cool and convert overnight. next morning too thick to check SG so screw it. it tasted sweet so I pitched my yeast. 2 packets fleishmans bakers yeast. no airlock on the igloo just left lid slightly open. had the most violent ferment I've evr seen. the grain kept rising to the top and crackling like i made a bowl too full of rice krispies. had to stir it back in many times a day. the whole mash started to overheat too! Never noticed this with my other ferments i guess cuz carboys dont insulate heat as well as igloos. temp of my mash hit 100. had no idea ferments generated that much heat. started puting ziplock ice packs in to try to cool it off. cooled it to about 85. kept swapping out ice packs for the whole day. ferment lasted about 36 hrs. all activity stopped, the grain fell my mash was cool so i proceed to strain and rack. heres the part that really stumps me. the first part was actually kinda fun navigating through all that, and watching a hyperactive ferment.

my sg was still 1.02 now that I've strained/racked I have my wash in carboy with airlock. no bubble activity on airlock. I thought maybe my yeast died becaused my mash overheated so much. so i pitched another 20 gm of distillers yeast. next day nothing. Now i know they say dont try to revive a stuck ferment by adding more sugar, and i was planning to go AG. but after repitching i was thinking there might not be any sugar in there in spite of the sg 1.02. so i dissolve 1.5 lbs of sugar in a little water and mixed it in. sg up to 1.04. 4 hrs later bubbling like crazy. I'm thinking i probably didnt even need to repitch yeast. i think all the sugar had fermented because the next day. all activity had stopped... again. and my sg was back down to 1.02... again. so anyways I'm stumped. how can all the sugar be fermented out but the sg remains 1.02? I'm gonna rack it again let it sit 2 more days and then distill it regardless of FG unless you guys suggest something better

[heartcut]

Dissolved or suspended anything the yeast don't eat will raise your SpGr. I think you're right, that wash was finished.

[noobshine]

could it be starch that didn't convert? should have had plenty of enzymes. have done 2 ag bourbon mashes that went from 1.05-1.00. I really thought I mashed it correctly.

[heartcut]

Hard to imagine incomplete conversion with that much enzyme available. Was the grain milled? I've had barley mashed at 155degF for 1.5 hr finish at 1.04 or a little higher, but your overnight mash should have split most of the long chain sugars. Bet it tastes good when you run it.

[noobshine]

Hard to imagine incomplete conversion with that much enzyme available. Was the grain milled? I've had barley mashed at 155degF for 1.5 hr finish at 1.04 or a little higher, but your overnight mash should have split most of the long chain sugars. Bet it tastes good when you run it.

I hope so. the temp going so high though I'm afraid it might produce some off flavors.
"was the grain milled" I had the guy at the brew shop crack it before he bagged it. I guess that's the same thing.
I saw a thread around here somewhere a while back that talked about what different enzymes do at different temps. but for the life of me I cant find it or remember much in it. If I recall the OP was suggesting that you should let your mash sit at different temps starting at 135 and going as high as 175 in increments of 10 degrees for 1 hr. that there was more than one enzyme and that they convert different nonfermentables at different temps. or maybe I read it wrong. maybe he was talking about different temps to extract the starch from different grains. like corn which you have to cook the hell out of. When I read it I was just starting this hobby, and it was way over my head. now I wish I could find it and wish I could remember who the OP was.

[Dnderhead]

Debranching (var.)

95-113°F
5.0-5.8 pH


Solubilization of starches.

Beta Glucanase
95-113°F
4.5-5.5 pH

Best gum breaking rest.
Peptidase
113-131°F
4.6-5.3 pH
Produces Free Amino Nitrogen (FAN).

Protease
113-131°F
4.6-5.3 pH
Breaks up large proteins that form haze.

Beta Amylase
131-150°F
5.0-5.5 pH
Produces maltose.

Alpha Amylase
154-162°F
5.3-5.7 PH
Produces a variety of sugars, including maltose.

[MitchyBourbon]

I have had an occasion or two to re-pitch yeast into what I thought was a stalled ferment. What I have found to be most successful is to make a starter which consists of some of the wort from the fermenter and some dme. Then pitch the starter when it is actively fermenting. That will give it the best chance to take off. If it doesn't take off then I conclude that it was done to begin with.

[noobshine]

Well eff me running... thanks Dnder. now these enzymes that do work at lower temps... are they destroyed at higher temps? in other words instead of striking at 160F and letting it cool naturally should we be doing the opposite and adding our malt at 95F and then slowly heating to 162 to allow for all that enzyme activity?

[noobshine]

I have had an occasion or two to re-pitch yeast into what I thought was a stalled ferment. What I have found to be most successful is to make a starter which consists of some of the wort from the fermenter and some dme. Then pitch the starter when it is actively fermenting. That will give it the best chance to take off. If it doesn't take off then I conclude that it was done to begin with.

good tip. thanks mitch. that would have prevented me from turning my ag into a sugarhead

[Dnderhead]

"should we be doing the opposite and adding our malt at 95F and then slowly heating to 162 to allow for all that enzyme activity?"
yes if you pitch malt at 150-169 your missing some.
but then it depends on the grain your using.
glucose/protein rest not necessary with most grains but good if doing wheat,rye and a few others.
beta amylase and alpha amylase both can be covered at 145f .that's the main ones.
so if wash is between 145 and 150 then when you pitch malt, it cools to 145F and hold it there.
1/2 hour is good but most time i "put the mash to bed" that is I throw a blanket over it and let it do its thing.until its cooled off on its own.then if doing a "on the grain ferment" pitch yeast (the only ferment i do on the grain is corn) others i rack into fermenter.then "sparg" (rinse) the spent grain
saving the "sparg water" to make the next mash with.doing it this way no sugars are missed and no diluting the mash.

[noobshine]

"sparge for my next mash"

nice, ive been smashing my grains over a colander into a bucket then pouring water over it and repeat. i'll just save that in the freezer for next time like backset.