Pressure Cooker Instant Pot Vanilla Extract Research

For those who are interested in my vanilla extract research, I will post that here and update it as needed.  

To start off, I’d like to thank all of you for your interest and continued support of this TIDBITS blog.  It’s exciting to see how the electric pressure cooker has made all of our lives so much easier and more delicious!

Given some recent attention that I have had related to my Pressure Cooker Vanilla Extract recipe, I felt it necessary to share the results of my research during the year before I posted the recipe, as well as information that I have gathered more recently.  My research focused mainly on the safety of placing jars of vodka inside a pressure cooker as well as the bacteria content of the extracted vanilla.  As always, I welcome your comments, suggestions, and any research results that you might have.

I’ll start with the alcohol 

The FDA requires a level of at least 35% alcohol to be considered an actual extract.  The USDA reports properly stored vanilla extracts life span to be indefinite.  To measure the alcohol content with “fingertip tight” bottles, I purchased a Hydrometer and Test Jar and measured the alcohol content to be 35 – 40% on several batches of extract using this Vanilla Extract recipe.  Furthermore, I brought in 2 bottles of vanilla extract (one of them about 6 months old) to the Bear River Health Department and they were tested for microbial contents. The results were negative.

Next is the more difficult issue of safety when cooking with spirits inside a pressure cooker 

Since the vapor released from spirits is flammable, the question of safety is a valid concern, and one should exercise caution.  I consulted with a Professor of Mechanical Engineering regarding this issue, and he offered the following opinions:

“At Marci’s request, I did some digging around to see if there was a risk of explosion while pressure cooking Liquor and Vanilla beans in an electric pressure cooker and utilizing the “natural release” method of de-pressurizing.  Since pressure cooking with Wine in a stovetop pressure cooker over a gas range seems to be accepted as safe (link), I used it as a baseline to compare against.  In writing this post, it is not my intent to get involved in blogger drama, but just to state facts, and let readers decide what is best for them.

For combustion, three things are needed: 1) Fuel vapor, 2) Oxidizer, and 3) Ignition source.  First, fuel: The temperature inside the pressure cooker is around 250 def F (link), well above the flashpoint of either alcohol (link), so flammable vapor/fuel is being produced in both cases. In the case of wine, the vapor is around 35% Ethanol (link).  With liquor, the maximum achievable in 95% in specialized distilleries (link).  For a stovetop pressure cooker, the gas is continuously released through the steam vent (a form of a pressure relief valve that trips at the desired pressure).  In the case of advanced electric pressure cookers (link), the cooking chamber is sealed so that it doesn’t release any vapor, and the pressure is controlled electronically. Second, oxidizer: In both cases, ambient oxygen serves as the oxidizer.  Third, ignition source: In the case of wine over a gas range, the ignition source is an exposed natural gas flame which burns at 3,500 deg F and is likely to come in contact with alcohol vapor.  With an electric pressure cooker, the ignition source is a metal coil at 1,000 to 1,700 deg F enclosed in the cooker housing, and is unlikely to come in contact with alcohol vapor.  Additionally, in the case of a “natural release” with an advanced electric pressure cooker, the alcohol vapor is released after cooking (i.e. when the metal coil is off), which further reduces risk.  The table below compares the two cooking methods.

In summary, there are always risks when cooking with flammable liquids. The amount of risk is likely related to the concentration of the vapor and the proximity of the ignition source. Cooking with wine near open flames is common practice and appears safe, likely due to the lower alcohol concentration of the vapor.  Cooking with liquor near open flames increases risk.  Cooking in an electric pressure cooker, however, reduces that risk by enclosing the ignition source. Advanced electric pressure cookers can further reduce risk by eliminating vapor released while cooking, and instead releasing the vapor after the ignition source is turned off (i.e. a natural release).”

I also consulted with the the UL Standards, and they responded with the following email:

Hi Ms. Buttars,

I’ve been asked to answer this question for you.  I did some research, and I can’t find anything definitively that says it’s unsafe.  I found a couple of cooking sites that have recipes posted for pressure cookers that appear to employ some alcohol. The UL Standard for pressure Cookers, UL136 is silent on this, as it  does not state any risks in the required “Important Safeguards” that forbid the addition of alcohol.  So I’m inclined to think it’s ok, but I can’t say for sure.  You might want to consider consulting the manufacturer of your pressure cooker to see what they say.  Hope this helps.

Best regards,

Nick DiFiore

Staff Engineer

Verification Services – Small Appliances

———————————————–

UL LLC

1285 Walt Whitman Road

Melville, NY  11747-3081

T:  631-546-2441

F:  631-439-6398

E:  [email protected]

W: ul.com

Other TIDBITS

I spoke with Utah State University Extension Services about cooking with alcohol and electric pressure cookers.  They stated that they are aware of recipes involving bourbon or rum and pressure canning, but as of that time, there was not a specific approved recipe for the vanilla extract process I was proposing.  

I spoke with Ball and Kerr to discuss the safety of using mason jars in an electric pressure cooker and they confirmed that their jars are safe to use in larger pressure canners and electric pressure cookers.

I emailed Beanilla about the best beans and alcohol to use, and this was their response (this is from 2 separate emails)

Hello Marci,

thank you for your email, below is an overview of the Madagascar vanilla beans different grades:

Grade A:

Moisture Content – 30% or more

Physical Characteristics – oily to the touch, flexible

Length – 13cm+

AKA – Gourmet Beans

Grade B:

Moisture Content – 25% or less

Physical Characteristics – rigid, stiff

Length: Less than 13 cm

AKA – Extract Beans

Essentially the vanilla beans can both be used to make extract, the main difference being the excess moisture present in Grade A. Grade B are also known as extract beans as they can not be used for any other application, however the vanillin content remains the same as Grade A. Typically, our customers purchase vanilla beans to make extract as well as to use the whole bean for baking / cooking etc… It is more efficient and economical for some of our customers to just buy a large amount of the Grade A and use in different ways, versus buying an extract grade and a premium grade.

—

To Summarize

My purpose here is not to convince anyone to make Vanilla Extract using my Electric Pressure Cooker Recipe, only to state the research I did before hand that made me feel comfortable doing it myself and sharing it with others.  If you are uncomfortable with the recipe, you can absolutely make wonderful vanilla extract using the traditional method of placing vanilla beans in a jar with 35% or greater alcohol and letting it sit for approximately 8 weeks.

I mention this in the actual recipe, but will repost this Caution here:

This method is NOT intended to be used with a stove top pressure cooker. Only use in an electric pressure cooker (that has passed the water test) with a FULL NATURAL RELEASE. Keep electric pressure cooker away from any open flame for the entire vanilla extract making process including when removing the lid after the Full Natural Release.

And there you have it!  If you have anything to add, I welcome your comments.  Thank you!