Wash jar lids and collars in hot soapy water, then sterilize jars in boiling water for ten minutes. If using new jars, you can skip this step!
Wash tomatoes, core, and slice into quarters. Peel and slice garlic cloves in half. Slice peppers into slices or slice in half, down the middle. Finally, wash fresh dill.
Divide tomatoes, garlic, dill, and peppers tightly inside the sterilized jars, layering the ingredients.
Add water, vinegar, salt, and sugar to a small saucepan. If adding alum, add it now. Whisk to dissolve the salt and sugar, until the pickling solution is hot. Allow to cool until warm.
Pour pickling liquid into the packed jars, leaving ¼ inch headspace. Wipe the rims and seal the jars. Refrigerate for 3 days to allow the flavors to meld.
