Fermenting on grain

[Blind Dog]

I've watched a few videos (are they even called videos nowadays?) and read a fair few books on making whisky and it seems to be standard practice, whether you spell whisky with or without an 'e', to ferment on the grains. Some then drain before adding to the still, some don't.

Just wondered why they do, whilst we brewers don't, or at least I can't find any reference to it. I can't think of an obvious benefit. Just find it intriguing.

(And yes I was good for a change and checked the topic is OK. But please abide by site rules in replying)

 

[bradsbrew]

I would assume that 'that' process dont care whats in the fermenter because they do not drink what comes out of the fermenter like us beer brewers do.

 

[superstock]

Aren't many native beers fermented this way.

 

[Bribie G]

Do you have grains?
Do you have fermenter?

Report back

 

[superstock]

Corn beer, beer made from corn, is a traditional beverage in various cuisines. Chicha is widespread in Latin America and some types use corn and are fermented and alcoholic, especially chicha de jora (a type of yellow corn).
I've done this. It is halfway to a process that's a no no.

Do you have grains?
Do you have fermenter?

Report back

You mean you have never done it?

 

[Blind Dog]

I would assume that 'that' process dont care whats in the fermenter because they do not drink what comes out of the fermenter like us beer brewers do.

If we're talking small scale, fair enough, but it's large scale commercial practice as well. The grain takes up a fair bit of space in a y FV which generally means higher costs. Plus it's a heck of a lot harder, messier to move thick gloopy grain / wort mix than just wort which adds further costs. So I figure there must be a benefit, I just can't figure out what.

 

[pist]

The only thing i can think of, is alot of scotch distilleries use a percentage of malt that has been smoked in peat moss. Perhaps fermenting on the grain helps further extract certain flavour compounds that are not accessible when the wort is pumped off the grains to the fermenter

 

[MHB]

As far as I know its far from common practice in Scotch making, I have read some reference to fermenting on the grist when making sour mash.
I have the CD for the Certificate in Distilling from the IBD, it is primarily focused on making Whiskey and Gin. It is pretty emphatic about very clear wash going into the still as breakdown products from grain and trub can create off flavours. It also discusses lautering in a lautering tun; the only difference to what we brewers do is that they tend to batch sparge 3-4 times and hotter than we do. The last sparge being sent to mash in the next batch. Clearly extracting tannins is less important than getting all the sugar they can.

There appear to be some interesting benefits when you are using a lot of adjunct, especially corn that has no Amylase, by sour mashing the enzymes that get denatured in the beer brewing process are still working in the fermenter, chipping away at the starch, the low pH suppresses moat and other bacteria.

I really haven't put a lot of work into sour mash not being a big Bourbon fan and a Scotch lover that's where my attention is focused. Perhaps someone with more information on American brewing practice could chip in.
Mark

 

[Kingy]

I would think the chances of infection are high fermenting on the grains. The flavours would be great tho. If it where to be infected it wouldn't matter if you where to distill it

 

[Benn]

I wonder if the undesirable bugs that would otherwise lead to a possible infection when fermenting on the grain could be killed off with a mash out at around 80 deg for 15-ish minutes ?

 

[TimT]

Really interesting. Of course the earliest fermented beers, Sumerian ale, were just this - grain cakes thrown directly into the pot with water (for the mash) and then left there during the ferment. I assume the cakes could then be used in later beers as a starter, as they'd make a very happy home for the yeast!

 

[MHB]

More bread than cake, probably looked a bit like pumpernickel, and I suspect more like porridge than bread after a week or two soaking in fermenting mash - aren't we lucky that brewing had moved on (No Tim resist the urge, it wont make for better beer)!

When brewing Saki there is a synergistic relationship between yeast and a fungus called Koji Kin (?) the Koji does what the enzymes do in mashing and protects the yeast from alcohol letting you make some ridiculously strong Saki. I am sure there are lots of microbes out there that will form beneficial relationships (am also damn sure the reverse is true), once you get low (<4pH) and some alcohol, and when you move from Aerobic to Anaerobic conditions, most bugs will be in trouble - but there will be some that thrive, there are going to be some very interesting effects - but it's outside my area of knowledge and real interest.
Mark

 

[schoey]

The handful of distilleries I've visited in Scotland all used a lauter to separate grain and wort and batch sparged multiple times as MHB mentioned above. Although I know the production of Chinese rice wine spirit ferments with the rice present so it wouldn't be a surprise to me if this method was used in whisky production as well.

The wash still used in whisky production requires significant effort to clean after use. Many distilleries also have a "brush" that constantly agitates the inside of the wash still so that the yeast and trub don't burn on. This would be difficult to do if grain was also in the still. If the grain was present in the FV then I would assume that most would separate the wash and grains at the end of fermentation.

The amount of energy required to bring the grain as well as the wash to distillation temperatures would be huge, so I doubt any modern distillery would transfer the grains into the still.

Also, pumping grain and wort together isn't difficult, just requires a heavy duty pump. Most larger modern breweries do this as the mash tun and lauter tun are separate vessels.

 

[tugger]

In commercial bourbon production they ferment on the grain and pump the wash grain and all into a continuous production column still that has heated slant plates to allow the wash and grain to fall to the bottom and be removed.
By the time the grains reach the bottom the alcohol is evaporated.

 

[QldKev]

I've never heard of a scotch being fermented on the grain, but I believe many bourbons are still made this way. With corn mashes up to 80% of the grain bill is made up of corn. By fermenting on the grain it allows the best utilization of the sugars, but also flavor from the corn. In most cases the corn is actually ground totally into a flour, so it isn't actually a grain bed, more like a corn soup.

 

[TimT]

More bread than cake, probably looked a bit like pumpernickel, and I suspect more like porridge than bread after a week or two soaking in fermenting mash - aren't we lucky that brewing had moved on (No Tim resist the urge, it wont make for better beer)!

Heh I actually did make a Sumerian ale once but, fool that I am, filtered out the bappir before fermenting.