Making kombucha can be a fun and rewarding way to enjoy a refreshing beverage while exploring the science of fermentation. But before you get brewing, it’s important to understand proper preparation and fermentation techniques to help ensure a safe, delicious final product.
Good news! The National Center for Home Food Preservation has published a research-based recipe for making kombucha tea at home. This recipe provides evidence-based guidance to help you brew kombucha while following recommended food safety practices.
pH is a scale from 0 – 14 that measures how acidic or basic a substance is. Using a pH meter at home may sound like a good idea, but it can actually make your food less safe. Here’s why:
1. pH Meters Aren’t Reliable Enough for Home Use
· Home (consumer-grade) pH meters can give readings that are off by a large margin.
· Even a small error can make the difference between a safe and unsafe product.
· This is especially risky for acidified foods like salsa or pickled vegetables, where pH must be precisely below 4.6 to prevent botulism.
· It is not just the liquid portion of the product that must be measured. Measuring pH of solids and liquids must be completed with the correct procedures (i.e. drain solids, record weights, blends solids, dilute with distilled water if needed, etc.)
· Home pH meters cost between $10 and $150 and are less accurate while professional ones range from $1000 to over $5000.
2. Professional Meters Need Regular Calibration
· True food-testing pH meters must be calibrated daily with fresh, lab-grade buffer solutions.
· Most home users don’t have access to the correct calibration materials or the training to use them properly.
· An uncalibrated meter = inaccurate readings, which can lead to false confidence in unsafe products.
3. Temperature Affects Accuracy
· pH readings change with temperature.
· Measuring hot or cold samples can give false results unless the meter automatically compensates for temperature — most home meters do not.
4. Cleaning and Maintenance Are Critical
· The pH probe must be cleaned, stored, and maintained correctly.
· If not, the sensor can become contaminated or damaged, leading to wrong readings or even cross-contamination between samples.
5. pH Isn’t the Main Safety Factor for Low-Acid Foods
· For low-acid foods, the time and temperature combination during processing, not pH, determines safety.
· Using a pressure canner, tested recipes, and correct processing times are what protect against Clostridium botulinum (botulism).
· pH is one of the factors used to set the targets for the amount of heat required during water bath processing, pH itself is not the target. Recipe validation requires a heat penetration study in order to determine the processing time, not just a measurement of pH.
· thickness of the mixture and size of the pieces also affects safety.
The Safe Choice
· Always use research-tested recipes from trusted sources like the National Center for Home Food Preservation (NCHFP) or other Extension services.
· Follow directions for processing time, pressure, and elevation adjustments.
· If a recipe depends on acidity, rely on measured ingredients (like vinegar or lemon juice), not home pH meters.
· A pH of 5.0 in vinegar does NOT mean 5% vinegar to be used in canning.
February 13 Webinar - Expanding Your Home Food Preservation Toolkit with Freeze-Drying
NCHP is excited to host a webinar on February 13 titled Expanding Your Home Food Preservation Toolkit with Freeze-Drying.
Thiswebinar will guide you through freeze-drying as a method of home food preservation.
Date: February 13, 2026
Time: 12:00–1:00 p.m. ET
Speaker: Andy Hirneisen, M.A., Distinguished Extension Educator and Team Leader, Retail and Consumer Food Safety, Penn State University
January 30 Webinar - Botulism: Home Canning Enemy #1
NCHP is excited to host a webinar on January 30 titled Botulism: Home Canning Enemy #1.
Thiswebinar will focus on botulism risks associated with home canning and reinforce research-based practices critical for preventing Clostridium botulinum in low-acid foods.
Date: January 30
Time: 12:00–1:00 p.m. ET
Speaker: Dr. Scott Whiteside, Food Systems and Safety Program Team, Food, Nutrition & Packaging Sciences Department, Clemson University
Mark your calendars and stay tuned for more information! Sign up information will be coming in early 2026.
Newsflash
Low-acid additions can make your jams and jellies unsafe—Here’s why:
Low-acid additions can make your jams and jellies unsafe—Here’s why:
When it comes to home canning, safety is more important than flavor. Adding low-acid ingredients—such as jalapeños (and even pickled jalapenos) or other low acid ingredients—to jams or jellies that haven’t been tested with them can make the final pH unpredictable. These types of changes could raise the pH to a level where harmful bacteria can grow. While sugar in large amounts can help slow microbial growth, safe preservation depends on the exact ratio of fruit to sugar to low acid ingredients and sometimes added acid. Without a tested recipe that accounts for the peppers, there’s no guarantee the product will be safe for shelf storage.
When canning, it is essential to use only recipes that have been scientifically tested and validated for safety. Below are two pepper jelly/jam recipes that meet these standards.
Please note: do not substitute the type of fruit in these recipes, as safety testing has not been conducted for variations.
A safe way to add extra flavor to your jams and jellies is by incorporating a small amount (1 teaspoon or less) of herbs or other flavorings into a tested fruit recipe. For example, basil can be added to strawberry jam, or vanilla to cherry jelly, without compromising safety. For more safe substitutions, please check out this guide: https://www.ndsu.edu/agriculture/sites/default/files/2024-03/fn2102.pdf
August 2025
Newsflash
Revised recommendations for stock/broth concentrates – June 25, 2025
Broth or stock concentrates, such as bouillon cubes, powders, or base pastes, should only be used in home canning recipes when the recipe specifically calls for liquid broth or stock—and they must be fully dissolved in water according to the manufacturer’s instructions before being added.
Key Points:
Broth and stock may be used interchangeably in up-to-date pressure canning recipes from reliable sources. Research accounted for the differences in broth and stock composition.
Reconstitute broth or stock concentrates by dissolving them in water according to the manufacturer’s instructions.
If the recipe does not include broth or stock as an ingredient, do not add any.
Do not add a bouillon cube or other concentrate that has not been reconstituted directly to a recipe.
Do not substitute broth or stock for other liquids (e.g., water, juice) in boiling water canning recipes.
Newsflash
Can I can ground turkey?
Can I can ground turkey?
Answer: The NCHFP does not have a process developed specifically for canning ground turkey. Ground turkey is approved for use exclusively in the Spaghetti sauce with meat recipe. This option does not appear in the USDA guidelines (last updated in 2015) because it was introduced after those revisions, so you will see this update in So Easy To Preserve and in our website but not at the USDA guide.
This is NOT a generalization that allows for other substitutions, like using the ground beef process for all ground turkey. This is a recipe-specific allowance and should not be generalized.
Newsflash
Is it safe for jars to be submerged in a pressure canner?
The National Center for Home Food Preservation advises that jars should not be fully submerged in water during pressure canning. Steam is more efficient at transferring heat when jars are not submerged, as it releases latent heat when it condenses on cooler surfaces. Too much water reduces steam, slowing heat transfer and potentially causing inadequate heating inside the jar. Tested recipes are designed for steam-dominant processing, and deviating from this could affect safety and effectiveness.
Note: Regular and wide-mouth Mason-type, threaded, home-canning jars with self-sealing lids are the best choice. Always follow the recipe. Some foods (e.g., smoked fish) may require more water, so adhere to USDA guidelines for specific foods.
SO EASY TO PRESERVE
The University of Georgia Cooperative Extension has now published a 6th edition of its popular book, So Easy To Preserve. The book was reviewed and updated in 2020. Chapters in the 388-page book include Preserving Food, Canning, Pickled Products, Sweet Spreads and Syrups, Freezing and Drying.
Calendar Reminder (link to .ics file download)