How can I know when my breath is bad?  I can't do it by putting my
hands up around my mouth and breathing out.

Hi sv4147,

Here are a few good ways to test your own breath at home:

1. Wipe the top surface of your tongue with a piece of cotton gauze
and smell that. (That's probably the most honest way.) Furthermore, if
you notice a yellowish stain on the cotton, it's likely that you have
an elevated sulfide production level.

2. Lick the back of your hand. Let that dry for about 10 seconds and
then smell. If you notice an odor, you have a breath disorder because
the sulfur salts from your tongue have been transferred to your hand.

3. Run a piece of dental floss between your back teeth (especially
where you may get food caught) and then smell the floss. This may be
an indication of the level of odors others may detect.

4. Stand in front of the mirror and stick your tongue out as far as
possible. If you notice that the very back of your tongue is whitish,
it may be a sign that you have bad breath. Also, you can judge the
reaction from others. Our patients tell us that they are no longer
offered gum and mints and people no longer step away from them. It has
significantly changed their confidence and improved their lives.

5. Ask the opinion of someone you can trust. Ask them to check your
breath several times daily because breath changes throughout the day.

6. If certain foods alter your taste, it is a good sign that sulfur
compounds are being produced. This usually happens after using Alcohol
based mouthwashes, eating dairy foods, drinking alcoholic beverages,
or after eating sugary products (Altoids, candy, Pepsi, etc.)

Source: 
How to Test Your Breath at HOME (for free)
Thera Breath
http://www.therabreath.com/art_testbreath.asp


Some interesting sites for you:

Animated-Teeth
http://www.animated-teeth.com/bad_breath/t1_halitosis.htm

Floss: Bad Breath Self-test
http://www.floss.com/bad_breath_self_test.htm

Mother Nature: Bad Breath - 16 Ways to Overcome It
http://www.mothernature.com/Library/Bookshelf/Books/47/9.cfm

Smell Well: How do I know when I have bad breath?
http://www.tau.ac.il/~melros/faq/20.html

Namura Medical 
http://www.natarella.nl/alitofresco/faq.html


Search criteria:
"know when i have bad breath"
"bad breath" test

I hope the information provided is helpful. If you have any questions
regarding my answer please don?t hesitate to ask before rating it.

Best regards,
Rainbow

I guess if I had googled the question myself I would have found the
same answers -- but I didn't.

Thank you for the tip.
Best wishes,
Rainbow