Is anyone batch feeding their fermentations?

[Gundog48]

I'm just starting up rum fermentations at our distillery. We normally make gin from GNS so this is a change for us. It's been recommended to me that we gradually feed in our molasses over the first 24 hours of fermentation to reduce osmotic stress. This idea is quite tempting to me as it would keep the yeast happy and allow me to get higher ABV washes which is obviously appealing at a small distillery.

The big problem with us is handling. Our original plan was to run out the molasses under gravity into our agitated blend tank via a 2" ribbed hose, combine with hot water to about 20°B, then pump via our diapraghm pump to an IBC tote fermenter. Pitch the yeast once the correct temperature has been met. 

Using a fed procedure, the start would be basically the same but with about a third of the molasses. It's then been recommended that we add the rest at about 2 hour intervals over 24 hours. We can't follow that strictly because we're not a 24-hour facility, but we could add larger doeses with a greater spacing. I'm not sure what kind of ABV we could push with this procedure using 493 EDV.

The big question is, how would you handle this? We could dose in undiluted molasses into the fermenter, but we would be likely to end up with undissolved lumps sitting at the bottom. So we would need an agitator, and would have to deal with agitating the wash multiple times per day, cleaning the agitator and the unavoidable spills. We could thin down the molasses, but then we would have to do that for each addition as diluted molasses would probably go off over a 24 hour period. We would also be adding  more volume with each addition.

I'm really interested in this process, but it obviously poses lots of challenges with our current handling capabilities. Has anyone got any advice they can share, even if that advice is "don't"?

[Coriolis]

Yeah, I use a batch feed system but it's not every 2 hours. Instead it breaks it up into four steps at roughly 8-10 hr intervals so a bit more user friendly for smaller set ups with limited man power. The guys at Lallemand gave me a protocol they recommend for ethanol production but it is equally valid for Rum. It's not really my place to post the document here but I'd recommend getting in touch with them and asking for it. I've had to modify it a bit to suit the way i handle my molasses but the principle is pretty much the same.

[Naked Spirits Distillery]

On 7/16/2020 at 10:06 AM, Gundog48 said:

I'm just starting up rum fermentations at our distillery. We normally make gin from GNS so this is a change for us. It's been recommended to me that we gradually feed in our molasses over the first 24 hours of fermentation to reduce osmotic stress. This idea is quite tempting to me as it would keep the yeast happy and allow me to get higher ABV washes which is obviously appealing at a small distillery.

The big problem with us is handling. Our original plan was to run out the molasses under gravity into our agitated blend tank via a 2" ribbed hose, combine with hot water to about 20°B, then pump via our diapraghm pump to an IBC tote fermenter. Pitch the yeast once the correct temperature has been met. 

Using a fed procedure, the start would be basically the same but with about a third of the molasses. It's then been recommended that we add the rest at about 2 hour intervals over 24 hours. We can't follow that strictly because we're not a 24-hour facility, but we could add larger doeses with a greater spacing. I'm not sure what kind of ABV we could push with this procedure using 493 EDV.

The big question is, how would you handle this? We could dose in undiluted molasses into the fermenter, but we would be likely to end up with undissolved lumps sitting at the bottom. So we would need an agitator, and would have to deal with agitating the wash multiple times per day, cleaning the agitator and the unavoidable spills. We could thin down the molasses, but then we would have to do that for each addition as diluted molasses would probably go off over a 24 hour period. We would also be adding  more volume with each addition.

I'm really interested in this process, but it obviously poses lots of challenges with our current handling capabilities. Has anyone got any advice they can share, even if that advice is "don't"?

We batch feed, but nothing close to your regime. We start at 10brix ferment down to 3 brix and add sugar and nutrient and get it back up to 10 brix. We do this twice. 

[Gundog48]

On 7/22/2020 at 3:29 AM, Coriolis said:

Yeah, I use a batch feed system but it's not every 2 hours. Instead it breaks it up into four steps at roughly 8-10 hr intervals so a bit more user friendly for smaller set ups with limited man power. The guys at Lallemand gave me a protocol they recommend for ethanol production but it is equally valid for Rum. It's not really my place to post the document here but I'd recommend getting in touch with them and asking for it. I've had to modify it a bit to suit the way i handle my molasses but the principle is pretty much the same.

I did exactly as you suggested and got that procedure, it looks great. One thing I'm wondering is whether you're using an agitated FV? Thinking about adding 100Kg of molasses to a 1000L fermentation without agitation sounds like a disaster! 

[Coriolis]

No agitation in the fermenter itself. I actually mix the molasses with as little hot water as i can and mix in a seperate vessel prior to pumping into the active fermentation.