Sour Mashing

[JohninWV]

The yeast thread got me thinking about sour mashing, specifically some of the comments by Denver Distiller.

We aren't sour mashing our whiskey. As we started up, our production was very sporadic but it's getting a little more regular now. I have been adjusting PH with lactic, but I'd like to try some sour mashing.

We pump all of our stillage into big stainless IBC's that our farmer picks up. They are fairly dirty as the farmer, nor his cows, seem to care. I assume I just need to find a clean container for some of my stillage.

Questions:

1. How much stillage are you putting back into the mash tank? Is it like 20% of the water volume?

2. What PH are you striving for once the stillage is in the mash tank?

3. Are you putting it in with the water prior to any grain addition?

4. Are folks still using nutrient even though a sour mash is supposed to be more nutrient rich?

What else am I missing?

[Denver Distiller]

1. 25% is the highest amount I've seen

2. 5.5 to 5.4 pH favors a and b amylase activity

3. You can add it any way you'd like, John. Remember that you can scald the beejeezus out of enzymes in the mash if you add it straight from the still. I'd be careful

adding it with barley present. IMHO, if you're looking for pH adjustment, you want to do it before you are looking for saccharification. That's when the pH is important.

4. Very astute question. You're passing nutrient (natural or otherwise) that has been consumed by the yeast back into the new mash. But you're only adding a maximum of 1/4 of the nutrient consumed back into the new mash. IMHO, you'll be able to cut back, but not eliminate added nutrient (Zinc, FAN, Ca, etc.). The percentage of malt you add will have an effect, too. The more malt, the less exogenous nutrient is needed.

Cheers.

[JohninWV]

What do you think the "shelf life" is...how long can I use it after it comes out of the still assuming we are using good sanitation practices in the storage vessel?

I'm sure it has to do with the temp it's resting and such, just looking for a ballpark.

I know in the summer time, our stillage was getting some mold outside really quickly. I'm not seeing it now that I'm keeping it indoors (it will freeze outside and is impossible to get out of the IBC at this point).

As far as addition time, I was thinking that most people add it in with the water prior to boiling corn. We won't add any hot stillage on top of malt.

[Denver Distiller]

What do you think the "shelf life" is...how long can I use it after it comes out of the still assuming we are using good sanitation practices in the storage vessel?

I'm sure it has to do with the temp it's resting and such, just looking for a ballpark.

I know in the summer time, our stillage was getting some mold outside really quickly. I'm not seeing it now that I'm keeping it indoors (it will freeze outside and is impossible to get out of the IBC at this point).

As far as addition time, I was thinking that most people add it in with the water prior to boiling corn. We won't add any hot stillage on top of malt.

Well, if you get one of those 55 gallon blue polyethylene drums I'm always talking about, you should be fine for at least a week. They seal completely, and a strong enough to survive the vacuum that will occur when it cools. I have a few that are over 8 years old, and they're still in great shape. I've never seen an infection inside mine, although I'm just using it for animal feed storage. Putting in the stillage at well north of 180F will take care of most organisms that'll spoil it. It's not ideal, obviously, to store it, but I think it'll work in a pinch. I'd fill one with hot water first, and check for any plastic flavor carryover first. I'm not using them to store stillage for reuse, so I'm not 100% certain that they'll work perfectly.

http://www.mcmaster.com/#storage-drums/=az0qig

Remember too, that you can choose to add thin stillage or thick, so you have to decide if you want to add more solids into your mash and wash still.

Cheers.

[Paul Tomaszewski]

Depending on where you are, this time of year you could freeze it and that'll extend it's lifespan. Since we load only liquid beer in our still (pot still), our SM is all liquid as well. We still use nutrients only because I look at them as an insurance policy. I've done some playing around with less/no nutrients and have had varying results, so I opt for using them. We put in the SM when we fill the water into our cookers and it gets boiled prior to adding grain.

[JohninWV]

Thanks y'all,