Could you explain your sour mash method?

[Artisan Still Design]

there are many mysteries and myths surrounding the sour mash process, however the simplest method I've seen is simply using spent mash to correct the pH while mashing. you would use far less then 25%, however in some circumstances such as extreemly low pH water it may take as much as 10% to correct as you moniter and maintain ideal pH throughout the mash process.

[Craft Distillery Resources]

There is the modern way of sour mashing, the old way of sour mashing and a mix of the two really. Depends on what style of bourbon or rye you are aiming for. I know of no small distilleries sour mashing the way the big distilleries do it. They sour the mash by screening the stillage to get backset which some add to the cooker and the fermenter, some just to the fermenter. 4.5 used to be the norm, around 5 is the normal ph now. If you are doing your job right on keeping lacto at bay, then your ph of your stillage should not be a whole lot lower than the starting ph of your mash. Years ago, 50 percent was the usual amount of backset, going way back, some used close to 100. In my opinion this is a big problem in the microdistilling industry. Nobody wants to sour mash, understands it, seems interested in finding out about it, and this is a main flavor component of good bourbon and rye white dog. Not to mention ups your yeild and keeps things clean and makes for less waste to get hauled off.

[Denver Distiller]

. I know of no small distilleries sour mashing the way the big distilleries do it. .

Sure you do. We do. Do it for our NS, too.

[Penrock Distillery]

So if it only takes 10% + - to correct the PH of the mash to 5(-ish), would this be enough to give the desired "sour mash" taste profile?
Im having a hard time understanding how these two factors work together. Can anyone clarify that such low backset % in the mash will give the desired taste profile or how exactly its done by the "big boys" ?

I have heard that Wild Turkey adjust their mash to around 5.8 at the start of mashing. Then they add 33% backset when the mash goes into the fermenter, which gives a PH of 5.1 as the yeast is pitched. BUT, In my very limited experience it would seem that 33% backset would drop the PH through the floor and dilute the OG of the mash. Apparently Wild Turkey said that it was a matter of quantities, but surly a 250 galling mash would work the same as a 20,000 gallon mash as a percentage?

I have also hear that in the wet milled cornstarch extraction industry it is common practice for an acid steep to be used as it reportedly increased starch yield by around 35%. So considering this fact would it be a safe assumption that a greater % of backset would produce a greater extraction of starch. But f this is the case then would the dramatically lowered PH inhibit a good & full ferment.

I hope you can see why Im a little confused.

[mendodistilling]

There are some good youtube videos of different ideas behind sour mash. leaving behind the yeast trub to start the next batch with, adding the sour dough bread idea to add acidity to keep the pH low enough to avoid spoilage risk.

[Artisan Still Design]

Wild turkey doesn't share much information so could be any thing from them may be a smoke show or 1 part truth and 2 parts deception.

met their master distiller and he wouldn't even admit what proportion of grains they used.

[Penrock Distillery]

Didn't the legal requirement for a "sour Mash" use to be 25% ? So if that correct how did that work, as 25% would drop the PH through the floor and affect the ferment surly ???. Or maybe the PH isn't such an issue as I think it is. I guess the only way for me to know for sure is to just experiment with test batches.

Id just like to hear how some of you guys do this process. Seems like there is indeed a lot of myth & secrecy surrounding Sour Mashing :-/

[Craft Distillery Resources]

I am working on a book on sour mashing to clear up the myths. The regs used to not tell you how much backset to use, but, it spelled out what was sour mash, and how long the ferment was, etc. 25 percent is about the normal amount used in KY. They all set fermenters around 5. If you keep lactobacillus out, your ph in the fermenter will not drop too much and the ph of the backset will not be to low. The only thing that should drop the ph is carbonic acid. If you have rapidly falling fermentation ph or you finish way lower than you started. That is indicative of a bacterial problem. The common method to sour mash today is with screened stillage. Added to the fermenter. Sour mashing is key to the right flavor of bourbon and rye. If anybody is having low ph, pm me. I can help fix that.

[PeteB]

Wild turkey doesn't share much information so could be any thing from them may be a smoke show or 1 part truth and 2 parts deception.

met their master distiller and he wouldn't even admit what proportion of grains they used.

I was there when you met Jimmy, if I recall correctly his answer to the grain question was "I have forgotten"

[OldSpye]

Barton, just for example, sours their mash cookers (but wouldn't disclose the percentages).

The bottom line on this is, I think, that there are virtually limitless variations that you can apply to the process. What works for you, in terms of flavor profile, is precisely what makes you unique.

Put another way - there's nothing "bad" except that which doesn't taste good.

[Penrock Distillery]

Thanks for your replays guys ! Much appreciated !

By what Ive been reading & what Ive seen, it seems that the PH isn't to much of an issue, especially if they mashed with 25%, 50% or greater in the past. I guess it will still ferment. Sounds like that the flavor profile of sour mashing is the main consideration with the PH coming in second. Please correct me if Im off base with this one.

Thanks Pop

[Artisan Still Design]

from the master distillers I've spoken too, sour mashing is for both PH control and consistency of flavor in the product.

[Craft Distillery Resources]

Backset buffers your ph. It helps keep bacteria at bay, holding your ph up.

[DSW]

Anyone have advice on a good system for screening the stillage? Is it even necessary to screen? Would it be inappropriate to simply let it cool and then pump it into the fermenter or cooker?

[JustAndy]

They are likely screening their stillage because the solids are used to produce dried distillers grain or other animal feed as a co-product. Depending on your scale the options are pretty different I imagine.

[Penrock Distillery]

Hello again.
Now that I'm on the brink of stating my distillery, I've been really trying to get my head round the "sour mash" method of corn whiskey (bourbon) production. Research has produced contradictory results if I'm to believe what I'm told about ideal yeast environment.

My initial understanding of the process was that you take a percentage of spent stillage (slop or back-set) from the still (10 - 25%) and add it to the next ferment. The rational bring that the acidic back-set lowers the mash PH to a level that promotes a healthy yeast environment .

But my experiments is that back - set is very acidic, sitting around 3.2 - 3.4 PH so would lower the PH to well below the level yeast are said to thrive in. So considering the pioneers of sour mashing apparently used up to 100% back-set in there ferments, how ever did their yeast survive?
Was the lowered PH of the mash intended to produce an environment so that when the mash was left left to accrue natural yeast strains, only the strongest would survive in such an environment thus providing as strong of a ferment as was achievable before  monitoring technology existed?

Perhaps the waters are getting muddied in these modern times with the big producers dictating how the method is said to work? Dare I say it might be mostly a marketing angle for them when in truth they simply employing the sour mash method to save on water consumption and reclaiming heat to cook the next batch of mash, only benefiting for the increased flavour profile as a bi-product of cost savings ?

[Penrock Distillery]

So considering the above, how is it possible for a craft distillery to employ a sour mash process in their whiskey production?
The only way I can see that might work, at least for me with the water that I have at my disposal, is to add the percentage of back-set to the cooker with the remaining volume of the mash water. Adjust the PH as you cook the corn so that when you pump into the fermenter the PH is at such a level that will promotes yeast health?
I'm also assuming the back-set needs to be screened before being added back to prevent an increasing accumulation of solids in your mash?

Any help would be very much appreciated as it's going my head in trying to sort the fact from the hype

[Silk City Distillers]

The impact is not as significant as you might think, as pH is not linear.  You also need to consider the buffering capability of the remaining water.  If you were mixing 10-20% backset with RO water (which you wouldn’t do), you might have a problem, otherwise, nah.

Grain adds buffering capacity as well, if you mashed into 100% backset, the pH would rise.

4.8-5.2 is a good starting pH range.  Don’t be afraid to pitch low - this allows yeast to thrive as they will outcompete bacteria (which can crash the ph).  This is totally counterintuitive, but one of the solutions to crashing pH is to start at a lower pH.

We add backset to the mash at the start of the cook, not after, I would never add it straight to the fermenter without additional pasteurization unless you can store backset somewhat sterile. For some products we add lactobacillus to the fermentation.  We’ve found lactobacillus brevis and plantarum to be positives if you are shooting for a creamy, toffee, buttery flavor profile.

They are both called sour - but the end results are very very different. 

[PeteB]

Here is an interesting article by Cowdry who was, maybe still is, on this forum, that he wrote back in 2011

http://chuckcowdery.blogspot.com.au/2011/02/buffalo-trace-demonstrates-another-way.html 

This is the way I have been souring my mash for the last 11 years, it is possibly the sour dough bread method mentioned earlier in this thread. I only occasionally add some of the previous fermentation.

Also mentioned above is using 100% backset, I tried that about 4 years ago in a single malt. It produced a huge amount of very interesting flavours. It is still maturing in barrels, probably for another year. I will decide then if I bottle it as a 100% sourmash or blend it with regular single malt whisky.

[SlickFloss]

We sour mash a lot of shit, anything we make we sweet and sour it. Our processes vary slightly by equipment set, mash in with water. Adjust with stillage to manufacturer recommended PH for TAA activity optimization. Adjust with water and stillage to SGA PH level for optimization. Complete any additions, cool to pitching temps, strap in for take off

 

cheers

[Bill Fender]

My experience in a big distillery was the stillage was screened to keep the solids low.  My plant manager told me solids build up was a problem.  (Wasn't smart enough to ask why.)  The 20-25% backset was added to the mash water.  It served two purpose, saved water and lowered pH.  No doubt it affected the flavor profile too.  The QC supervisor told me to be sure and keep the backset hot preventing mb growth.  A simple static screen will provide the separation required for a small plant.  Big plants use a centrifuge and get most of the solids out.  We had a great yield and it was due to constant sterilizing the cookers, mash lines and fermenters.  Micro bugs will kill you.  

[Southernhighlander]

2 hours ago, Bill Fender said:

My experience in a big distillery was the stillage was screened to keep the solids low.  My plant manager told me solids build up was a problem.  (Wasn't smart enough to ask why.)  The 20-25% backset was added to the mash water.  It served two purpose, saved water and lowered pH.  No doubt it affected the flavor profile too.  The QC supervisor told me to be sure and keep the backset hot preventing mb growth.  A simple static screen will provide the separation required for a small plant.  Big plants use a centrifuge and get most of the solids out.  We had a great yield and it was due to constant sterilizing the cookers, mash lines and fermenters.  Micro bugs will kill you.  

What big distillery was that? With corn based spirits it's best to ferment and distill with the solids left in, which is why Jim Beam, Jack Daniels and the other big distilleries do it that way.  Our mash tuns, stills and fermenters, for grain bills that are mostly corn, are all set up for on the grain mashing, fermenting and distilling and that equipment is in around 300 distilleries.  On the grain is best for Bourbon and other corn based distilled spirits because it is so much easier and less time consuming than trying to remove the solids.    Also many of my customers sell the grain in, spent mash with the liquid left in to hog farmers.   

One of the main reasons that the vast majority of corn derived spirts are done on the grain is because the corn for corn spirits is not malted.  You can put 500 gallons of cooked bourbon mash above a false bottom screen and you may drip out 10 gallons of wort. The only way to get penetration with a sparge on corn mash is to add 20% rice hulls which is a huge waste.  It is so much easier to just do it on the grain.  For spirits distilled from malted grains such as Barley and Wheat etc, fermenting and distilling off of the grain works great.

[Bill Fender]

I worked at Brown-Forman Distillery 19 years, plant engineering manager.  I think you confused mash with backset.  Backset is screened to remove solids in all of the operations I'm aware of.  As I mentioned, most all big operations use centrifuges for very high suspended solids removal, of backset.  Suspended solids removal also enhances evaporator performance.     

[adamOVD]

Pretty sure he's saying they separate the solids from backset before adding to the next batch, not that they ferment off the grain. Thinner mash is easier to pump around, and too many solids stress the yeast in your ferment.

[Bill Fender]

2 minutes ago, adamOVD said:

Pretty sure he's saying they separate the solids from backset before adding to the next batch, not that they ferment off the grain. Thinner mash is easier to pump around, and too many solids stress the yeast in your ferment.

Exactly, thanks!