Ok, I stumbled upon this old post a few days ago for the first time and read the entire 30 pages in one sitting. I instantly wanted to try and contribute to this experiment because as of yet the goal of this post hasn't really been accomplished. After many hours of researching I decided to try my hand at a recipe this weekend. I have several attempts lined up but this is the first one, and I figured I would post my process to help narrow brewing without malt down a little more.
The experiment was for a 1 gallon batch, using sweet potatoes as the enzyme source, and allowing for an extended mash time. I decided to go for a heavier "grain bill" and brew a darker styled beer to help hide all of the off flavors that are sure to be present with this process. The following is the "grain bill":
1 x 7oz. Sweet Potato
1 lb. pearled barley
1 lb. Quick-Barley
3 oz. Quick-Oats
5 oz. Molasses
5 oz. 6-Row Malt (added later, read on)
I did not have iodine or test the PH levels as I did not expect I would need them, however, next attempts will definitely have these added in to make sure I have something more quantitative. I will simply transcribe the notes I took during the process...
Sweet Potato Enzyme extraction:
1. 7 ounce sweet potato, peeled and diced into small pieces.
2. Boiled 2 cups tap water, let cool to 110F and added water and sweet potato chunks to blender.
3. Pulsed in blender until the consistency of grits. Temp dropped to 85F.
4. Poured mixture into small pot, stirred periodically for first 15 minutes. Then let sit for 15 minutes to allow chunks to settle as much as possible.
5. Using turkey baster, extracted juice from sweet potato mixture, and set aside.
6. Added 2 cups of 130F water to potatoes and placed pot on stove top on low heat, stirred and heated until temperature brought back up to 130F, held at 130F for 5 minutes while stirring, turned heat off, put lid on and let sit for 20 minutes.
7. Extracted juice as before and added to first runnings. Repeated same process for 150F.
8. Now have a total of approx 5.5 cups of sweet potato juice (enzyme water)
Mashing Phase:
1. Poured 3 of the 5 cups enzyme juice back onto sweet potatos, and added 4 cups spring water and 1 lb of pearled barley. Put on stove top and slowly heated to 159 degrees. Took gravity reading while heating up (at 115F) to establish a base and mixture read 1.000.
2. After took gravity reading, took most barley out with a slotted spoon and some of the water and placed in blender and blended for approximately 15-20 seconds. Then added back to pot and continued mash.
- Note: 10 minutes into mashing at 159F, mash is getting starchy.
4. Turned off heat, stirred, covered, let sit for 20 minutes.
5. Temp after 20 minutes read 150F, stirred, and added 3 oz. quick oats, 1 lb of quick-barley, and 8 cups spring water, attempted to bring to boil. Stirring constantly as mash wanted to burn on bottom.
- Note: After 15 minutes of attempting to raise temperature enough to boil it was obvious it wasn't going to happen without burning the bottom really bad and ruining the batch anyway. So took temperature at 170F and turned heat off.
6. Added 1/2 cup enzyme water, and 3 cups spring water, stirred, temp at 145F, covered, let sit until temp reached 135F (approximately 30 minutes).
7. Added 1 cup enzyme water and 1 cup spring water, stirred, temp dropped from 135 to 128F. Covered, let sit 2.5 hours.
8. After 2.5 hours temp read 114F. Added remainder 1/2 cup enzyme juice, stirred, put lid on, and let sit 1 hour.
9. After 1 hour, turn on heat and slowly raise temp to 129F. and held for 30 minutes.
Here is where the primary usefulness of the experiment ends. At this point I am a total of 7 hours into the process, and over 4 hours into the mash. After 4 hours it is obvious that the starchy mess is not getting converted enough. It IS getting a little sweeter and if I had more time I would've continued and let it sit until it all converted but I did not have time. So at this point I diverge from the restrictions of this thread and add a little 6-row to see if I can save it and still try my recipe....
10. Added 3 oz. 6-Row Malt to mix, and kept heat between 135-145F for 4 hours, stirring occasionally.
- Note: 2 hours in it was obvious of the change the 6-row was having. It was still starchy looking but the mix was having a clear layer begin to appear on the top 1/2 inch or so after sitting on its own for approx 20 minutes, as well as tasting sweeter as time went on, so I continued to let it work.
11. After 4 hours, strained the entire mixture and discarded the grains. Added the strained mixture back to pot on stove top, and added 2 more oz. of 6-Row malt and 6 cups hot tap water. Stirring, slowly heated to 148F.
12. After holding at 149F for 30 minutes, stir, cover, let sit overnight (8.5 hours)
13. In morning, strained mash one more time (produced 10 cups total), added 12 cups hot water to 10 cups wort, mixed and took gravity reading. Gravity read 1.020. Put on stove and brought to boil. Boiled for 90 minutes.
14. Added 5 oz molasses, put into fermenter, topped up with spring water to 1 gallon, shook for several minutes to aerate, took gravity reading: 1.043.
15. Sprinkled on 1 packet of fleishmanns dry bread yeast, Fermentation took off within 45 minutes.
So without the iodine testing, a lot of this experiment is sort of mute. I did note that after fermenting overnight the trub settled out, of which there was a TON. I'm wondering/hoping if what i percieved as a "starchy consistency" was just all of the unsettled trub in the mix, because it was pretty sweet by the time I gave up on the sweet potatoe enzymes and started adding 2-Row. Oh well, I suppose a taste test of the final product will be the only way to know for sure at this point.
And for those curious, this will be bittered with coffee, and flavored with roasted hazelnuts. I'll post pics and notes of the final product as well as the future experiments to get this process to work.