Rapid Infusion

@Chris - I have been infusing alcohol (grain spirits) for some time now and came upon 2 "rapid infusion" techniques; with an iSi or Sous Vide. Using the soak and wait technique takes about 45 days, hence my intrigue with these methods. I tried both rapid techniques and had what I would call perplexing results. I should also add that after the infusion, the alcohol was mixed with a milk/cream simple syrup.

iSi - Using lemon (zest only) and grain alcohol (192 proof). I did a 4 minute infusion with NO2 then mixed it with the SS and it was absolutely silky smooth. There was zero "bite" from the alcohol. My question here is why is it so smooth compared to soak and wait technique where you would still taste/feel the "bite" of the alcohol. What effect does the NO2 have on the alcohol that would cause this? My concern is that through some reaction, I'm significantly changing the alcohol content. Is that the case or am I way off-base?

Sous Vide - Using the same amount of zest and alcohol that I used in the iSi, I vac'd the ingredients and sous vide them for 1 hour at 125º F. After the hour, the bag was put in an ice bath to cool. It clearly infused and looked the same as the iSi trial. I then mixed it with the same amount of SS mixture as in the iSi trial and the results were FAR different! This had a significant "bite" from the alcohol. I'm wondering if the zest didn't infuse enough? What to do to resolve this? I would have expected a more mellow result based on the fact that it was cooked a bit.

Any comments/direction would be appreciated!!!

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Comments

Chris_Young_80640

@Keith_Pietranczyk

We cover some of the science behind the iSi technique here:

http://www.chefsteps.com/activities/pressure-infusion-with-charred-oak

As to your question, I can assure you that you are not getting a chemical reaction between nitrous oxide and ethanol, nor is the alcohol content changing. It's more likely that the sugar and milk are suppressing the volatility of the ethanol (reducing the bite). It's also known that fat and sugar suppress our ability to perceive the "strength" of the alcohol.

Is it possible that this is what's going on? Or perhaps I'm not entirely following your questions.

Brendan_Lee_56950

Could be a difference between the strength of zest your using as well. I imagine that heating the mix would change things as well. Maybe a better test would be iSi infusion vs 4 minutes total of pressure infusion from the chamber vac so you could rule out heat as a factor. So how I would do it at home would be to put the alcohol and zest in a container big enough to not allow it to bubble over in the chamber, pull a full vacuum time it and then repeat as many times necessary to equal 4 minutes.

Not terribly exact since the chamber and the iSi have different pressure capabilities but it may help rule out heat as a factor.

Sumit__65166

maybe it's the temp difference? the vapours from warm alcohol is making the drink bit more potent.

polkachef74

@Chris - That is possible. I guess I was just caught off-guard by the results, that's all. Often happens in experiments, you think its going to be one way and you wind up proving the other.

brent.kidwell

As a follow on to this, I'm making a batch of limoncello and would like to avoid the long wait time at room temperature for the infusion to occur by heating the alcohol (I'm using Everclear) sous vide. I've read the section in MC about this, and for an "extract" the book recommends 122 F for citrus zest for 3 hours. I've read a few articles about others attempting similar extracts, and it seems the temp varies up to about 156 F (with warnings not to exceed these temps) and anywhere from 3 - 8 hours. Before I went down this road I wanted to ask if anyone has experience or advice about cooking temps and times to accomplish the extraction needed for limoncello? Thanks much.

Chris_Young_80640

@Brent — Different temperatures and time will give you slightly different flavor profiles, but as to which is "best" it will be entirely to your preference. If possible, try to prepare a few very small batches to see what you like. If it were me, I'd probably start by preparing 100 g samples of the following:

122 °F for 3 hours and 6 hours

132 °F for 3 hours and 6 hours

142 °F for 3 hours and 6 hours

152 °F for 3 hours and 6 hours

polkachef74

@Brent kidwell I was making limoncello and understand the wanting to sous vide. You gain in being able to create more volume than with the iSi. However, I will say that the iSi at 4 minutes produced the best flavor. Many folks don't like the harshness of the grain alcohol. The iSi relieves that and produces a very smooth product. The down side to the iSi is you are limited to how much you can make per batch (approx. 1L) and you have the added cost of the NO2 chargers. But if the cost is acceptable, I think the iSi is the best method.

brent.kidwell

Thanks very much, Chris and Keith.

I paired the lemon zest with 750 ml of 100 proof vodka and cooked it sous vide at 135 F for approximately 10 hours. I chilled the result and added approximately 16 ozs of simple syrup. Just pulled it from the freezer for a taste, and it is very good. There's undoubtedly room for improvement, but this was a good first try.

Johan_Edstrom_5586

This reminds me of my friend driving his tractor through the shed perfecting Obstler when I lived in Bavaria