Off-Flavours From Plate Still – Pilbara Conditions

[Kylek90]

Hey everyone,

Looking for some help troubleshooting some off-flavours coming out of my plate still. The below details are how I normally run the still and have always had good success. However, every now and then I have a dud run, generally around summer. Hopefully someone can spot what I’m doing wrong.

Wash Details
• Wash: 50L TPW
• Sugar: 11.25 kg
• Starting pH: 5.51
• Starting SG: 1.062
• Final SG: 0.990
• Fermentation temp: Kept inside an air-conditioned house (set at 22 °C) then had a heat belt wrapped around the fermenter holding it at 30°C.
• No visible infection or strange smells, fermented out clean, then left to sit for 2 weeks.

Still Setup
• Boiler: 50 L milk can
• Column: 4" neutraliser with 5 plates
• Packing: 500 ml section before RC packed with copper mesh; RC tubes also packed with copper mesh
• Heating:
Two elements: one halved to 1200 W, the other 2400 W
2400 W element on a voltage regulator
• Cooling: Mains water in at 30.7 °C, out of the column at 33.2 °C

Run Details
• Wash was transferred the night before using a transfer pump and cane (approx. 48 L total) — no sediment carried over.
• The next morning, I loaded all plates and then dialled back the main element to 169 V.
• Held full reflux for 30 minutes, then backed off RC water until I had 2 drips per second takeoff.
• Collected ~600 ml of foreshots/heads before hearts started coming through.
• Increased voltage to 200 V for a steady toothpick-sized stream.
• Vapour temp at the elbow between condensers: 77 °C.
• Room temp: 22 °C, with aircon blowing directly onto the elbow.

Issue
• Product was initially 95% ABV and tasted clean and neutral.
• Around 1500 mls in, ABV dropped to 93%, and the flavour started to turn tailsy.

Any ideas on what could be causing the flavour change this early in the run?
High incoming water temp??

Appreciate any insights — cheers!

[Wellsy]

Hello Kylek

Firstly why not pop into the welcome centre and introduce yourself formally.

So everything is going fine until you increase flow to toothpick size, problem is toothpicks come in all shapes and sizes. chad morgan for instance uses garden hose as floss. What flow rate are you collecting at when things go amiss ?

[bluc]

50l wash? I would expect about 2-2.5l hearts from that. How much heads you collect? What takeoff speed and wattage on heating?

People doing neutral, most strip first when doing neutral. run the still as fast as ya can, collecting down to 20abv or lower at the spout. Then add the stripped alcohol, low wines, to boiler 20+ l at time or more. You well end up with better seperation of the factions and much more hearts, obviously makes for longer day though.

[kingy]

If the coolimg water is warm it needs more reflux with more water flow to have more liquid on the plates and more power to keep the collection rate up, if the reflux ratio is to low and your collecting to fast alcohol percentage will drop as its letting tails through, if my water tank is warm like in the middle of summer I need good flow otherwise the rc nearly boils the input water and I get air bubbles in the line and the still starts playing up. When that happens i open up the water flow to get full reflux and then bump the power up.

[Kylek90]

I collect at roughly 2L to 2 ¼L per hour and it had been running happily at this rate up until 1500mls. I noticed that the percentage started dropping off and the tails were carrying across.

Discarded 600mls of fore shots & heads. I used 3600 watts to heat up then dial it back once the plates are loaded. I'm not sure how many watts it's using at the above off take.

I'd like to do stripping runs but just don't have the time.

I've been running the still the same way for the last couple of years but during summer is when I seem to have issues. The ground water here in the Pilbara gets really hot. I'm wondering if this is what is causing the flavors to carry over.

Thanks "Kingy" I'll muck around with the RC flow rates next run.

[TheRealMrMessy]

Welcome! Good array of info there to give some advice.
I'm in FNQ and have an immediate suggestion on the fermentation step for a sugar wash - switch to angel red yeast. Takes a little longer to ferment out vs bakers but it can handle up to 42c. Shouldn't need to keep it in the AC then. I regularly have fermenter temps in the 38-40 range and it turns out fine.

Remove the packing from your RC. Increase your water flow or decrease your power - but packing the RC can result in unwanted side effects and it acting like another packed section. I tried it, had weird results, removed the RC packing and it solved the issue. I also have hot "cooling" water, sitting 25-28c out of the tap and packing the RC didn't help its knock down power - I can still run 2800-3500w and it handles things even with that water temp.

All the copper nice and clean? 5-5-1 can help you and helps remove more sulphides.

Generally, you'll have a better result if you strip and then spirit run. It's all about that 10% or so impurities coming over. Cleaner that 10% is the less it'll influence the taste.

Last thought - add a thermowell to your boiler, watch the boiler temp too. While you get various warning signs of tails from your column temp and fogging of glass, you get lots more warning when you can monitor the boiler temp.

[Kylek90]

Thanks "TheRealMrMessy" heaps of good suggestions.

I'm heading to Perth next week and going to swing into a brew shop, I'll grab some angel red and give it a go in the next couple of washes.

I'll remove the RC packing and give it a crack next run along with increasing the RC water flow.

I clean my copper after every 4th run, got one more run to go & the plates don't look too bad yet.
I generally just use a strong dose of citric and vinegar. But do still have some peroxide, I'll give the 551 a go again.

Seems like I'm going to have to find the time to do the stripping runs. :D

[RuddyCrazy]

Also mate learn to use your nose instead of tasting as what comes off the still the angels need to have a drink first off :laughing-rolling: as generally what they do drink we didn't want anyway :handgestures-thumbupleft: so make plenty of cuts put some paper towel over them and visit the next day or so.

[Kylek90]

Haha yeah, they get there far share.

[TheRealMrMessy]

I'm actually in Perth for work right now haha, well Freo but close enough. I'll reach out when back home next week.

Regular home brew might not carry angel red, but the bigger groups online do - kegland, beerco etc. Means postage but I use about half the recommended equivalent to bakers yeast, so a couple 500g bricks go a long way. That isn't what makes it take longer (edit: I've tried higher starter rates to no benefit), just every time I've used it, its taken about 1.5 to 2x as long. Trade off worth it for me.