I have a 20 gallon batch of 100% corn (30 lbs and 15 gallons of water), which was cooked on 5/31. OG: 1.058 (seems a little low to me) pinched Red Star Distillers yeast (30g) next day to allow to cool around 90 degrees. Mixed well, today 6/7 checked SG = 1.014 (again seems to high after nearly 7 days fermenting....a few bubbles are continuing however I am thinking fermentation is close to being done.
1. Why is it taking so long to finish fermentation? Fermentation Temp is right around 74-76 degrees....
2. What is the target OG reading on a mash cook?
2. Did I not use enough yeast?
We are a start up and I am running test batches to get things dialed in, so today I am using city water (particulate filter in the line already), water conditioning guys coming next week to install a softner as well as RO. I will not be using RO to mash.
Cooked another batch on 6/5 (again OG was 1.058, waited until 6/7 (this morning due to working 6/6), there was a nice thick cap on top (thinking natural fermentation started) so I continued to pinch yeast, this time increased to 40g Red Star.
I'm not sure if those questions can be answered right away without more info. A ferment at 75F is a little lower than most seem to run their distiller's yeast at, but 1058 isn't bad conversion at 2 pounds per gallon especially if it's one of your first and you're still getting the process down. 2 grams per gallon doesn't seem unreasonably small amount of yeast assuming it is viable.
Here are a few more questions:
How finely ground is the corn?
What temp did you cook to and for how long?
What enzymes did you add at what points in the cook and mash and at what temperatures and what pH?
Did you check the pH of the ferment? Did it crash low enough to stop the yeast activity with the 100% corn and no added buffers?
Eud, thank you for your posts and comments......
Corn is milled at the mill, I would say fine similar to that of corn meal.
120-130 struck in the corn and added Termamyl 4.5 oz. then took mash temp up to 185 and held for 60-90 min. Allowed mash to cool to 150 and added 9 oz Saczyme Pro then cut heat and allowed to cool while agitator was running to continue to mix mash.
To be honest - I did not check the pH after cook nor during ferment. I will be going to get a pH tester today - What is the required chemical to adjust pH up or down based on readings?
I have thought about using 95% Corn and 5% Malted Barley for the buffer.....thoughts?
Home distillers just use oyster shells (designed as chicken feed) from the feed store as a calcium carbonate source to raise pH during the ferment. Calcium carbonate doesn't dissolve much in water until the pH drops, so just adding chalk will keep it from bottoming out during the ferment. More tweaks and measuring and multiple batches of experience will let you keep it stable.
Usually enzymes are picky about pH. You might consult the data sheets on your enzyme and then check pH when you add the alpha enzyme and also when you add the gluco enzyme. You might need a little citric acid or backset to lower it for the gluco enzyme in particular and to start off the ferment at below 5pH. Then you might need some calcium carbonate to keep it from crashing during the ferment.
By the way, I'm more familiar with the enzymes from Ferm-Solutions, and those quantities are really high for a 30 pound mash using the liquid enzymes they sell. I don't know those brand names, though, so maybe that's a reasonable amount.
Not sure 5% malted barley would be enough buffer for a pH crash. Not saying it won't. I just don't know.
Gotta neutralize that chlorine in the city water too. I found that aerating it for 24 hours usually does the trick if you don’t have another neutralizer.
Ditto on the PH testers. That’s a big deal.