Their are 3 ways to do do this that will yield good results:
- Cold brew the tea and add it to primary or secondary
- Add the Rooibos during flame-out
- Add the Rooibos to the boil
We highly suggest the first method, as this will preserve most of the distinct aroma and flavor you mentioned. If brewing a 5 gallon batch of beer, we suggest the addition of 1/2 gallon of brewed Rooibos liqour - brewed with 75g of Rooibos overnight in cold water!
This method has the additional benefit of adding liquid and minute fermentable sugars to primary.
Your alternatives methods (2 & 3), have a few disadvantages;
method 2 will add more bitterness to the beer, though it will keep more body and require less tea (about 50 - 60g).
Method 3 will add the most bitterness, and you will loose almost all of this spice and floral notes that create the unique flavor from Roiboos. It has the single advantage of requiring minimal tea (about 40 - 50g, any more than this and it will be overwhelmingly bitter).
Here is a link about cold brewing tea-link
Also, if you can, try to add honey in the primary when the beer is about 60-70% done with fermenting. Use a Hydrometer to find the fermentation point.
When you add honey in the boil it adds mouthfeel, but not much honey flavor which would complement the Rooibos flavor. As the yeasts start to ferment the types of sugars(maltose, glucose, etc.) which are slightly different from the honey. The yeast will get used to that type of sugar and when you add the honey to the primary less of it will be fully fermented adding more honey flavor to your beer.
Answered by: The Gastrograph Team