What is the correct way to do Acid Starch Hydrolysis?

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SUMMARY

The correct method for acid starch hydrolysis involves using hydrochloric acid (HCl) at a concentration of 1 molar, heated to approximately 180°F for an extended period, ideally around 24 hours. For home experimentation, a mixture of 1 lb of corn, 2 lbs of water, and 1/4 cup of vinegar can be boiled for 30 minutes to convert starch into sugar, yielding maltose. Testing for sugar presence can be done using a wine maker's hydrometer, which indicated a reading of 1.040, sufficient for fermentation. The discussion emphasizes the importance of using enzymes or malted barley for effective starch conversion, as corn alone may not yield maltose efficiently.

PREREQUISITES
  • Understanding of acid hydrolysis processes
  • Familiarity with fermentation techniques and yeast behavior
  • Knowledge of sugar testing methods, such as using a hydrometer
  • Basic chemistry principles related to temperature and reaction times
NEXT STEPS
  • Research the use of amylase enzymes for starch conversion in brewing
  • Learn about the industrial processes for acid hydrolysis of starch
  • Explore the role of malted barley in whiskey production and fermentation
  • Investigate the effects of different acid concentrations on starch hydrolysis
USEFUL FOR

This discussion is beneficial for home brewers, food scientists, and anyone interested in fermentation processes, particularly those looking to optimize starch conversion in corn-based recipes.

gary350
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I have tried corn mill, now I am trying corn from a grocery store can.

I tried 5% vinegar, now I am trying 40% hydrochloric acid.

Heat to 150° F for 2 hours. Starch should turn to sugar but it is not working?

I don't know how much acid to use to make this work?

1 lb corn + 2 lbs water + acid + 150° F for 2 hrs

What am I doing wrong?
 
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How do you test for the presence of sugar? (And what do you mean by sugar? glucose?)
 
Borek said:
How do you test for the presence of sugar? (And what do you mean by sugar? glucose?)

I have been tasting it. I have not done Iodine test yet because it taste like water. If there is sugar should I not be able to taste it? I wonder if too much acid will destroy starch? What is the correct about of vinegar for 1 lb of corn + 2 lbs of water. The thick sticky mixture has been turning to water mix like it should but no sugar taste? Grocery store corn in a can is cooked is that a problem?
 
Today I tested sugar with a wine makers hydrometer i get a reading of 1.040 that is enough sugar to make 5.1% alcohol in fermented wine. After doing more research I learned the sugar I am getting is MALTOSE that is why I can't taste it. No iodine to be found the pharmacy does not sell it anymore. I did more test with grocery store corn in a can needs 1/4 cup of vinegar is all the acid that is required for 1 lb of corn to convert starch to sugar. Bring to a boil for 30 minutes it is finished, sticky glue corn mixture turns to water & corn. Pour through a strainer, save liquid, throw away the corn. The starch white milk color is no longer there. I added yeast soon I will learn if Maltose sugar will ferment. Sugar could be concentrated to a high hydrometer reading 1.086 by boiling off some of the water to get 12% alcohol.
 
gary350 said:
Sugar could be concentrated to a high hydrometer reading 1.086 by boiling off some of the water to get 12% alcohol.
Won't the alcohol boil off first?
 
epenguin said:
Won't the alcohol boil off first?

Boil the water & vinegar off before fermenting it. Boiling is a wine makers trick since the law does not allow the addition of sugar to commercial wine you squeeze out juice then boil off water until sugar becomes concentrated enough to give you the high alcohol you want in your wine. Boil water away until syrup is thicker than honey then add water again to get a hydrometer reading of 1.086 for 12% alcohol or 1.090 for 12.6% wine. Law does not apply to home wine makers they can use sugar if they want.
 
Why don’t you let the yeast hydrolyze the starch from the corn grit? That’s how bourbon is made. Why are you trying to malt with acid? I don’t think you are getting maltose from corn. Barley - maltose and glucose. Corn - Glucose
 
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chemisttree said:
Why don’t you let the yeast hydrolyze the starch from the corn grit? That’s how bourbon is made. Why are you trying to malt with acid? I don’t think you are getting maltose from corn. Barley - maltose and glucose. Corn - Glucose

Whiskey is made with 70% corn, 20% barley, 10% rye. The process soaked in 100°F water until barley germinates. There is enough enzyme in malted barley to convert some of the corn starch to sugar. One of the experiments in high school chemistry 50 years ago was to heat corn with acid at a certain temperature for certain length of time so acid will convert all the starch to sugar. That was 50 years ago my brain does not work well anymore. I have forgotten more than I ever knew. I don't remember how this is done? I tried vinegar. My industrial chemistry book says to use Hydrochloric acid. I tried Hydrochloric acid too. I don't know how much acid to use, I don't know what temperature to cook it, I don't know low long to cook it? 50 years ago I had a man show me now he did it using vinegar. He mixed 1 pint of corn meal with 1 gallon of water when it began to boil he started adding vinegar and stir well. He stirred the mix and kept adding vinegar for 30 minutes. Cooked corn meal is like glue very thick then it changes to water & white color. Keep stirring and adding vinegar, keep adding vinegar until all the white color is gone. That is the trial & error method. LOL I was hoping to learn the exact amounts of each, corn, water, acid, temperature, time, without doing trial are error method? I also think the mixture needs something extra like yeast nutrient to feed the champagne yeast to get 20% alcohol. Chemistry book says, add enough sodium bicarbonate to neutralize acid. Sodium bicarbonate is not easy to find at a reasonable price I wonder if baking soda will work but it has a horrible flavor.
 
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Baking soda and sodium bicarbonate are mostly the same thing.

Acetic acid is IMHO too weak for an efficient starch hydrolysis.
 
  • #10
The industrial acid hydrolysis is done with 1molar HCL at ~180F for hours, like 24 hours! Hate to do that kind of thing at home when I can just add some malted barley or a few oz of amylase enzyme at 120-150F for an hour or so. These things are widely available at brewing supply stores. There are several in my city or I can order them online.

Bulk bicarbonate is cheap in the laundry isle.
 

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