Trying to perfect a potato mash

[OBJ]

Hey Guys,

I've been working with this potato mash recipe that I developed and I'm trying to get it perfect but I'm in need of a little help. I've done 4 batches so far, hardly got anything out of the first 3 and only got a little out of the 4th. I'll copy the recipe below and then I'll elaborate on my yields, etc.


50 lbs Potatoes(the kind I've been using are about 17.2% starch for a total of 8.6 lbs of starch per 50 lb)
.2 oz BA-100
.2 oz GA-100
2.5 packets Turbo Pure 48 Yeast
Citric Acid
Baking Soda
Iodine
2 packets anti-foaming agent

1. Add potatoes to 12 gal pot. Add just enough water to cover potatoes. Boil for an hour.
2. Drain but save water. Mash up potatoes.
3. Replace water and stir well. Allow to cool.
4. While cooling, adjust PH to 5.6.
5. Once cooled to 74*c(165*f), add BA-100. Stir well.
6. Allow to cool slowly (at least 1 hour from 74* to 65*)
7. Once cooled to 65*c(149*f), adjust PH to 5.3 and add GA-100. Stir well.
8. Allow to cool slowly over next hour.
9. Test for starch conversion with Iodine.
10. Cool quickly to 25*c(77*f). Transfer to fermenter.
11. Add 5 gal water
12. Adjust PH to 4.8-5.0.
13. Test SG, % sugar, and PABV.
14. Pitch 2.5 packets Turbo 48 yeast.
15. Add 2 packets anti-foaming agent.
16. Ferment


As I said, the first 3 batches didn't yield much. I had a few problems during fermentation that needed correcting, ie, airtight fermenter, temp control, etc. I was pretty certain that I was on the right track by the time I got set up for my 4th attempt. The 4th batch fermented, but not fully. The initial SG was 1.033, and SG after fermenting (7 days at constant 80*f) was 1.009. I estimated my ABV to be around 3-3.5%. I'd like to get an ABV of at least 4 or 5%. From what I've read, that is not out of the question with potatoes. And I'd like to get that final SG down below 1.000.

I feel like I'm getting closer but there are a few things I'd like to try differently. Here is a list of changes I'm thinking of making:

1. Different yeast. I've read on here that Turbos may be too quick and I'd be better off with a slower acting yeast. I have a big bag of Liquor Quik with AG but I've never used it and don't really know what it's good for (Ok, I used it once in a sugar wash and it gave me blue spirit, I stopped messing with it after that.). I'd like to use Fleischman's because it's cheap and available. Not sure on how much I should use for this mash. Any advice here?

2. Use yeast nutrients. I have never used these and could use some clarification on their benefit. What types to use is a mystery to me, I've read a little about miracle grow or DAP but still unclear.

3. Don't add the 5 gal of water in step 11. I have been doing this because it seems like a thinner mash would be better but I think that not adding it would boost my initial SG and help boost the final ABV. But would the mash be too thick? Does it matter?

4. Use more enzyme powders. I'm thinking maybe increasing from .2 oz to .5 oz will give me more complete conversion. The iodine test has been showing complete conversion but I don't know if I trust it. Is there such a thing as TOO much enzymes?

I really can't think of anything else that I could change to make this mash yield more. Any other advice would be great! Is it possible that 3-3.5% is as good as it's gonna get? I hope not. Has anyone else had any great success with their potato mash?

Thanks for the help,

OBJ