Aussiedistiller, Home Distilling, Moonshine, Home Brew

Hey guys, here’s one for the Single Malt distiller’s here.

I’m having trouble fermenting out my AG Single malt washes. To date, I’ve done 3 and they all have done exactly the same thing.
So, I’m using
4kg of Joe White Traditional Ale malt,
2kg of Simpson medium Peat
5g yeast nutrient
10g gypsum
2 Tbs of Safspirt Grain yeast
My water is soft with minimal mineral content

I mash for 90 mins at 64°, sparge and have 24ish liters at 1.060SG
Pitch the yeast and fermentation kicks off in roughly 6 hrs. Fermentation continues happily at 20-25° for 3-4 days, and then slows to a stop. FG has stalled at 1.020, and I haven’t been able to get them to go any lower.
I’ve tried pitching more yeast, raising the temp to high 20’s, and still no success.
I checked the ph, and they all come in around 3.3-3.4, and the have a strong sweet/sour smell and taste. I tried adding some calcium carbonate, but that didn’t help either.

So I believe that my ph is crashing during the fermentation, and killing off my yeast. But I have not been able to find any info on how to stop it, despite exhaustive searching. I’ve never had this problem with 30+ beers that I’ve brewed, but all 3 single malts have done the same thing.

Any ideas or suggestions on how to prevent this from happening on future attempts?

Get some clean stockings muslin cloth or biab/paint strainer bag. Buy some shell grit put it in bag and suspend it. Should keep ph in check. I just found out the hard way if you just toss it in it builds up(unless your very good with guestimation). Check out the link in my Sig for few more ideas on getting it going. What yeast you use btw?

I'm unfamiliar with either of those malts but 1.020 isn't excessively high, have you run it though a calculator to see what it should finish at?
I rarely get much under 1.020 but I use ale malt and some adjuncts
@3.3 pH your yeast should be fine but possibly a higher pitch rate might help. Aiming for a higher abv than beers the pitch rate also needs to be higher or the yeast get fat lazy and don't finish strong.

coffe addict wrote:get fat lazy and don't finish strong.

Sounds like me :laughing-rolling: :laughing-rolling:

Do you oxygenate your wort before pitching yeast?
how old is the yeast and how is it stored, airtight and in the fridge?
2 tablespoons in 24L of 1060 wort seems excessive.
Have you checked your thermometer for accuracy?

I had the same issue using US05. I worked out I was under pitching. I increased by a third and now ferment out dry. ;-)

Thanks for the replies guys,

I'm using Safspirit GR-2, with a use-by date of 05/2020, Stored in the fridge of course.
From my beer brewing experience, for a starting gravity of 1.060, 2tbs (22grams) should be about right. But i'm happy to try more or less...


Where would I get shell grit from?


I tried to strip one of the washes on the weekend, and I had nothing but trouble with it. It foamed up like crazy, and puked, bringing a large amount of color and solids over in the distilate. It also had a very unpleasant smell.

It's disappointing to have wasted nearly 20kgs of grain! :angry-banghead:

Cheers guys.

Nearly all my all grain stripping runs puke. Dont worry too much it will clean up nicely on the spirit run. If it is really bothering you, leave a little head room in the boiler and pop in a knob of butter into the boiler each stripping run, puking will minimise or completely stop.

Shell grit can be found at produce places and more expensively at pet stores

A ph in the low 3s isn't a problem. I do lacto kettle sour beer all the time at 3.1 or 3.2 with us05.

1020 isn't super high either. Though I'd expect it to go to 1010 or just under. Maybe try adding amylase to the ferment?

Unpleasant smell is likely from an infection and again a higher pitch rate will out compete bacteria for the available sugars.
To put it into perspective for you a rum wash uses 80gm of yeast!
With beers serious attention is paid to sanitation so the yeast doesn't need to compete against bacteria. In Distilling we approach it differently and ensure that pitch rates are high enough to out compete. This is because the higher sg's and we don't need to bottle or keg ot and have it sitting around usually we boil the wash pretty soon after its finished. The higher pitch rates have the added advantage of quicker and hotter ferments producing acids helpful in the creation of esters another thing usually avoided in beers.

Interesting points, Coffee...

I really need to do more mashes! Inconsistent results has me second guessing myself...