Coffee's effect on yeast.

[Boogdish]

This question stumped the owner of my LHBS and I couldn't find anything useful doing a search.

I was planning on doing a coffee stout and adding some brewed coffee to my secondary. I was planning on bottle conditioning this stout and I was wondering what effect the coffee will have on the yeast? Would it be better to add it before fermentation is done while the yeast still have some food? And how much coffee is too much?

 

[suprchunk]

I have had no problems with carbonation and coffee in the secondary. And as for the amount, it depends on how much coffee flavor you want. I've added ground coffee straight in and strong-brewed liquid in in varying amounts. A few ounces go a long way.

 

[TipsyDragon]

according to John Palmer in How To Brew you can steep 0.25 to 0.5 pounds of fresh ground coffee over night in the fridge in 1-2 quarts of water. then add it to you bottling bucket on bottling day with a normal amount of priming sugar. the juices you get from the coffee is unfermentable. of course this if for a 5 gallon batch and you would pour the coffee through a coffee filter when you pour it into your bucket.

 

[DavidHawman]

Caffeine from the coffee increases yeast lifespan: http://www.ncbi.nlm.nih.gov/pubmed/18513215

Don't know what this means for brewing though...