Indiana Cottage Food Water Activity and pH Requirements

The Two Numbers That Decide Whether Your Recipe Is Legal

Under Indiana's Home-Based Vendor law (IC 16-42-5.3), you can only sell foods that don't require temperature control for safety — classified as non-TCS. Whether your specific recipe qualifies comes down to two measurable properties: water activity and pH.

If your product's water activity is at or below 0.85 or its pH is at or below 4.6, it may meet the non-TCS threshold and you can sell it from your home kitchen without a retail food establishment permit under the HBV framework. If both numbers exceed those thresholds, the product does not meet this non-TCS screen and may be TCS — it can support the growth of dangerous bacteria at room temperature — so selling it under the HBV exemption is not allowed.

These aren't arbitrary cutoffs. Below pH 4.6, the acid concentration in your product prevents the growth of Clostridium botulinum, the organism that produces the toxin responsible for botulism. Below water activity 0.85, there isn't enough available moisture to support bacterial reproduction. Either threshold can be the controlling factor, but the exact recipe and process still determine whether a product is non-TCS or needs refrigeration to prevent foodborne illness.

What Passes and What Doesn't

Products that reliably fall within the non-TCS thresholds:

• Traditional full-sugar jams and jellies (the sugar binds water, dropping water activity well below 0.85)
• Cookies, brownies, and most baked goods without cream fillings or custard
• Fruit pies with standard pastry crust (not custard, pumpkin, or cream pies)
• Hard candy, fudge, and caramels
• Dry noodles and dry pasta
• Pure honey and maple syrup
• Dry herbs and spice blends
• Bread and rolls

Products that typically fail the thresholds:

• Cream cheese frostings and buttercream containing a TCS ingredient
• Custard pies, pumpkin pies, and cheesecakes
• Fresh fruit or vegetable juices
• Low-sugar or sugar-free preserves (not enough sugar to reduce water activity)
• Flavored oils (can support botulism if garlic or herbs are added)
• Cut fresh fruit

The gray zone is where people get into trouble. A custom frosting recipe, a specialty fruit spread with reduced sugar, or an herb-infused vinegar can fall on either side of the line depending on exact proportions. "It seems shelf-stable" isn't evidence. You need actual lab numbers.

Getting Your Recipe Tested

If there's any uncertainty about whether your recipe meets the non-TCS thresholds, get it tested before you start selling. The Purdue University Food Science Department provides state-approved water activity and pH testing services specifically for home food producers. They'll test your product, issue a lab report with the exact values, and that report becomes your documented evidence if a health department ever questions your compliance during a complaint investigation.

To get tested through Purdue Extension:

1. Contact your county's Purdue Extension office or the Food Science Department directly
2. Submit samples of your finished product (prepared exactly as you would for sale)
3. Receive a written lab report with water activity and pH values

Keep the lab report permanently. If a consumer files a complaint and the local health department investigates, a certified process authority report is your strongest defense. Health departments will ask for it.

Beyond Purdue, you can use any process authority recognized by the state. The key is that the testing must be done on your specific recipe — not a similar recipe from a cookbook or a generic product category. Changing an ingredient, adjusting sugar ratios, or substituting a sweetener can shift the numbers enough to cross the threshold.

What HEA 1424 Changes Now

Since HEA 1424 took effect on July 1, 2026, the Homestead Vendor framework (IC 16-42-5.4) exempts qualifying vendors from state time-temperature control regulations. This means homestead vendors with gross annual sales under $1.5 million can sell perishable, TCS foods directly to consumers — prepared meals, cream-filled baked goods, and items that are prohibited under the HBV framework.

That doesn't mean water activity and pH stop mattering. Even under the current framework, local health departments retain authority to investigate foodborne illness complaints. If your product causes someone to get sick, the scientific properties of your food may still matter to the investigation. Understanding your recipe's risk profile is still smart practice — it's just no longer the legal gatekeeping mechanism for qualifying Homestead Vendor sales.

For HBV products, these two numbers remain the regulatory fork in the road. The Indiana Cottage Food & Home Food Business Guide includes the complete product evaluation framework — TCS vs. non-TCS decision tree, lab testing contacts, and the labeling requirements that follow from your product classification.

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