DAP added to wash

[BCarter]

BCarter, when would you add the DAP during a Tomato Paste Wash ferment?

No worries! Sorry, should have clarified that one.

It's pretty easy really. You add it, when you detect H2S on the nose. It should clear up pretty quickly, dependent on the ferment (type, volume, yeast, ferment rate etc).

The trick is, knowing when H2S is being produced. It can quite often smell like a normal ferment. We usually add it if we have an inkling of H2S, purely due to the minor lag phase, to ensure the H2S won't get any worse...

By mid-ferment, I meant somewhere after ferment had started...if you don't detect signs of yeast struggling (H2S production), then you won't need to add DAP. You can add DAP before ferment has begun, to minimize your lag phase of beginning fermentation, but this is a minor effect. If you add at the beginning of fermentation, it's usually because you know there will be H2S problems mid ferment.

There's a few important things to remember...if you perceive H2S from the ferment, but it's fermenting quite quickly...don't add DAP...it's what we call 'stress by population'...that amount of H2S will blow off towards the end of ferment, as the yeast consume the sulphides for amino acid production.

Which brings me to the next point...if the ferment is slowing towards the end of ferment, as long as H2S isn't being produced, you won't need to add DAP...just find a way to warm the ferment to get it dry...this may be a problem for distillers...residual nitrogen in the ferment after it is dry is inviting to spoilage organisms, which may produce acetaldehyde. If there is a lag time between end of ferment and distillation for low wines, you'll get slow degradation of quality of the wash for distillation.

In short:

Yeast producing H2S --> Slowing of Ferment --> Lack of CO2 protecting ferment --> Ethyl Acetate and Acetic Acid production from Oxidised Ethanol and Spoilage

(Ethyl Acetate and Acetic Acid degrading of Ethanol share in wash. H2S, causing larger heads portion).

and

Residual Nitrogen Post Ferment --> High Nitrogen, Low Sugar, High Micronutrients from Yeast Hulls --> Bacterial Growth --> Acetaldehyde and Diacetyl Production.

(Acetaldehyde and Diacetyl real pains to separate, as detection threshold is very low).

The aim of our game is separation of alcohol...these steps (although being fine details), aid in maximising the ethanol separated in distillation, and the ease at which high % v/v can be extracted.

[nb0s]

Hi bcarter

I thank you for your informative posts. This forum is richer for your information. As is evident by this thread being a sub thread of "Sugar washes" my comments within this thread only refer to TPWs and as TPWs are used for neutral spirits, congenors, as you quite rightly point out are not a required product of the final distillation.

Please note that TPWs are usually one of the first washes that are attempted by "newbies" as they leave the clutches of the HBS. They need the process to be kept as simple as possible and mid ferment additions is not simplification. Whilst most will recognise H2S as that commonly referred to as rotten egg gas, not everyone here will necessarily do so. Personally I have never noted my TPWs struggling and like many personal use home distillers I ferment inside my home (the temperatures are more even). I can assure you my wife would strenuously object if my ferments were producing H2S

You very nearly say this but for the "newbies" out there please state that for the vast majority of low alcohol TPWs the addition of DAP is not required.

Regards

[BCarter]

Hi bcarter

I thank you for your informative posts. This forum is richer for your information. As is evident by this thread being a sub thread of "Sugar washes" my comments within this thread only refer to TPWs and as TPWs are used for neutral spirits, congenors, as you quite rightly point out are not a required product of the final distillation.

Please note that TPWs are usually one of the first washes that are attempted by "newbies" as they leave the clutches of the HBS. They need the process to be kept as simple as possible and mid ferment additions is not simplification. Whilst most will recognise H2S as that commonly referred to as rotten egg gas, not everyone here will necessarily do so. Personally I have never noted my TPWs struggling and like many personal use home distillers I ferment inside my home (the temperatures are more even). I can assure you my wife would strenuously object if my ferments were producing H2S

You very nearly say this but for the "newbies" out there please state that for the vast majority of low alcohol TPWs the addition of DAP is not required.

Regards

You're very welcome!

You're completely correct, if you're looking at simple, easy distillation, don't worry about DAP...

If you want to jump into more advanced, technical distillation...looking for more purity and higher quality distillate, then it's a good idea to have some DAP in your arsenal of ferment tools.

[batbrew]

DAP and other micronutrients are added commercially to cane sugar fermentations which contain no nitrogen source. Yeast will battle to ferment in a solution containing just carbs. It needs a nitrogen source which is where the DAP comes in. Even with this source it is likely that sulphides will be formed particularly in higher gravity /temp fermentations. Often activate carbon is used to help remove these sulphurs. Purging with CO2 can also help.

Copper is good at converting sulphurs into copper sulphate which also helps strip sulphurs

DAP should be added at the start of the fermentation - often a formulation containing DAP and other yeast nutrient - I believe these may be mixed into what is called turbo yeast?