Asparagus (beer)

[Pocky]

As a home-brewer located in the Netherlands, I am involved in a brewing project aimed at creating a beer with asparagus syrup as one of the ingredients.

A food technology student and myself were asked by a asparagus farmer to come up with an idea to create a beer that pairs nicely with an asparagus meal and that also contains asparagus. For this purpose we used an asparagus concentrate. It has a syrup consistency. One ounce of this syrup is the equivalent of one kilogram of fresh asparagus.

We added the an ounce/liter syrup to the mash of a blond ale. So far so good ... However, during the fermentation the beer develops a very strong sulfur odor. Smell could be described as egg/rubber.

Does anyone on the forum have any idea what causes the strong sulfur smell and if it can be avoided or fixed?

Thanks!

 

[shoreman]

What yeast did you use? Some yeast (German ale and lager yeasts) can throw off those sulfur/rotten egg smells during fermentation but will clean up with age.

 

[Pocky]

Thank you Shoreman. We have tried various (Belgian) ale yeasts. All resulting in sulfur smell.

 

[shoreman]

Sounds like some sort of yeast by product - what if you tried something neutral like Nottingham or a Chico yeast and ferment at low temps - low 60s

 

[Homercidal]

I wonder if the veggie has a high sulfer content that in turn causes the yeast to produce a high sulfer aroma. You know like when asparagus causes your pee to smell funny?

 

[CreamyGoodness]

I adore this idea. I made an asparagus mead once that did have a little bit of a sulphur smell to it (not a heck of a lot) after clearing at @3-4 months. I just added asparagus to the breadyeast mead recipe I had been playing around with instead of a concentrate or syrup though...

For this reason I would have to agree with Homer... I think this is a function of the vegetable, not fermentation/yeast.

Homer, would you think introduction of O2 during fermentation (ie, like in a coolship) or stirring with a copper rod would help the OP?

 

[Pocky]

My assumption about the sulfur content in the asparagus is the same. We have tried various yeast types all resulting in the same sulfur smell. So my guess is that we would have to find a way to reduce it. Winemakers sometimes use copper salts (sulphate) to get rid of it. As a home brewer I don't want to play around with chemicals. However, if O2 can do the job I would definitely be interested in learning more about it.

Thanks again guys!

 

[Homercidal]

I can't say much, but I've heard some people use copper tubing specifically because it's supposed to react with their finished product as it dribbles through it and remove the sulfur flavors. Supposed to provide a smoother and cleaner flavor. I don't have any evidence that it actually works like that, but that seems to be common knowledge in that endeavour. So much so that I wouldn't design a device without it, just because.

As far as O2, there is a point at which the yeast might not be able to consume all of the O2 in the beer, and it would therefore provide a very negative flavor through oxidation.

I would let it ride and see what happens before jumping into any crazy experiments. It may be that the yeast does a complete job at ridding the beer of the sulfur in due time. If tricks were employed with the intention of helping it out, there is no basis for understanding the yeasts effectiveness. Perhaps a future batch, if warranted, could provide fodder for further studies.

 

[CreamyGoodness]

Always take beer advice from Homer before myself, OP.