QUESTION:

Hi,

How does the pre-wet affect coffee taste? More specifically how does the percent of volume and pre-wet directly change the taste profile?

Thanks

Jeffrey

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ANSWER:

Great question Jeff!

To answer your question, pre-wet affects coffee in several ways I will try to explain this in the easiest terms possible for clarity.

 Pre-wet allows the ground coffee to absorb water which makes the coffee swell up and release carbon dioxide once the carbon dioxide has been released water can more easily penetrate the coffee and extract the desired soluble material from the coffee grounds. It can be used to overcome common issue related to brewing coffee.

• Eliminate dry pockets caused by fresh roasted / fresh ground coffee. Fresh roasted / fresh ground coffee may still be degassing (Releasing CO2) thus creating dry pockets when brewing; the water is literally repelled by the gas. As mentioned before pre-wetting helps release this gas preparing the grounds for greater water absorption through the rest of the brew.

• Helps to overcome issues with decaffeinated coffee. The processes used to remove caffeine from coffee, leaves the coffee (for lack of a better term) denser making it more difficult for water to penetrate the coffee particles thus restricting the extraction process. Thus a need to introduce pre-wet.

So this basically explains the process and what it does to coffee but that does not answer your original question which was how does it affects taste.

To answer that is much harder because every coffee is different and has different needs with regard to pre-wet for a proper extraction. Then there is the human factor because everyone tastes are different. In a nut shell there are no hard and fast rules. But there are some basics to this.

Ultimately one of the biggest affects pre-wet can have is balancing acidity sometimes people would describe coffee that is acidic as bitter, strong, harsh etc. So to help balance this we can introduce pre-wet. You can cut the acid a little or almost eliminate it completely or you can develop a smoother more evenly extracted cup of coffee that is pleasant to most palates. Pre-wet can also give coffee more body (sometimes referred to as mouth feel) a nice balanced cup not only tastes good but feels good in the mouth.

Now because every coffee will react differently to the percentage of pre-wet and the delay of the pre-wet there are a couple things that I find helpful when I am flavor profiling.

When it becomes evident that pre-wet is needed or desired I like to start at about five percent this is a good general starting point and it generally insure enough water to saturate the grounds the next thing is I will select a 10 second drip delay.

I then run a batch of coffee and observe the flow of water out of the brew basket I like to see the coffee slow to a drip but not stop completely. If coffee is still flowing at more than a drip before the next pulse lengthen the pre-wet delay. If it stops before the next pulse increase the percentage of pre-wet (10 second is as low as programming on a FETCO brewer will allow you to go with the pre-wet delay). Once you have achieved a slow drip before the pulse that follows the pre-wet then taste your coffee and adjust from there never adjusting more than one parameter at a time.

By no means has what I provided been what could be considered an exhaustive list of possibilities but it is a start. I truly wish I had a silver bullet for you but one just really does not exist. This process is a matter of experimentation and more experimentation.

I hope with this information and some basic starting points this can help you with your flavor profiling needs. If you have any additional needs please feel free to contact me and I promise I will not allow your e-mail to slip between the cracks again.

Shane Blais & Logistics