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Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 7:25 am
by keriruri
The recipe was: 5Lt blackstrap molasses, topped up to 25Lt in the fermenter with tap water, 20g distillers yeast (usual strain for rum, placed in warm water for a while first). I didn't add nutrients as I'd read in this forum that molasses provides enough nutrients for the yeast. Before adding the yeast I stirred everything up well to aerate.

First 24 hours bubbled away nicely, maybe two and a half days all up with the airlock burping. But the last few days almost nothing and now, day 7, no action.

I put the SG thing in and it didn't sink down to the green line the lady in the brew shop said it needed to (see picture). I don't have a pH meter. I put the hydrometer in and it didn't even sink to show a degree of alcohol.

Questions: Do I add another 20g of yeast? Do I add nutrients now? Is it too late to add nutrients and if not, what do to add? Or, should I just run the still?

This is my first ever wash. I've done a tonne of research (recipes, read the forums) and would hope to keep things very simple for future processes. ANY constructive advice very welcome!

Re: Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 8:38 am
by Rock
Maybe temperature is the issue. I've not used anything but bakers yeast and i would hsve pitched up to 80 g into 25lt wash.
I've not started rum yet , because I use a large fermenter, i wait for the ambient temperature to help with fermenting.
Unlikely ph will be a issue being a gen 1 wash.

Re: Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 9:24 am
by Sam.
Rum will finish with a high gravity due to unfermentables.

You need to take a gravity reading at the start and the end and the difference will determine what’s fermented.

Give it a taste and see if it’s still sweet or if it’s dry, I am betting it’s done :handgestures-thumbupleft:

Re: Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 9:39 am
by gad
How much raw sugar was in the recipe ?
Sugar & molasses should be all you need with first generation. I would have started with 80g of bakers yeast.

Re: Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 9:45 am
by bluc
I am guessing its done also 5l mollasses in 25l not lot of fermentables. mollasses is only 52% fermentable on average. 7-8l without extra sugar is very do able.. were you using heaters? I have had it finish in 3days in hot weather. 7 days in winter definately do able..

Re: Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 12:06 pm
by nuddy
Echoing what everyone else has already said.
5L of molasses is approx 3.6kg of fermentable sugars. (1L molasses = 1.4kg, 5L x 1.4kg = 7kg, molasses approx 52% ferm sugars, 7kg x 0.52 = 3.6kg)

3.6 kg ferm sugars in 25L vol not a crazy amount of sugar as bluc mentioned. Be around 8-8.5% abv. More than likely it’s ready to run. Give it a taste, if it’s dry on the tongue will have fermented out.

Re: Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 12:55 pm
by bluc
Being lighter brown like dirty water rather than jet black could be an indicator also :handgestures-thumbupleft:

Re: Help! Rum wash crashed...I think.

PostPosted: Fri Aug 02, 2019 8:53 pm
by keriruri
Thanks for the feedback, everyone. On day two the temperature did drop to around 22 degrees, so I put it on a heat pad and then covered it with a couple of woolly jumpers and it rose to around 26-28 degrees for the last few days. On your advice, I've tasted it and it is not sweet at all. So tomorrow morning will run it through the still..first time, wish me luck! Also next wash I'll increase the amount of yeast I add. I'd prefer to stick with molasses only, and not add sugar, so maybe will look at increasing the amount of molasses as well...happy to hear opinions...