Table of Contents

• Section 1. How to Do a Viable Plate Count
• 1: Why we need to dilute
• 2: Setting the stage: Diluting Cold Press Coffee
• 3: Working out the dilution
• 4: Overall dilution
• 5: Design a dilution!
• 6: How to scale back up
• 7: Count a plate!
• 8: Why plate more than one dilution?
• 9: Picking the plate to count
• Section 2. Practice Problems
• 10: Putting it all together
• 11: Quickies
• 12: Is the water safe?
• Section 3. Review
• 13: Summary

Quickies

Below, you can practice a couple more times. Also included are a few unusual situations ... things do go wrong, of course, and you should be able to recognize that. If you think the dilution series is not valid, click on "re-do the dilution". Lastly, "TMTC" means "too many to count".

 

dilution factor	1:100,000	1:1,000,000	1:10,000,000	1:100,000,000	Re-do dilutions?
count	TMTC	674	68	7
answer

 

dilution factor	1:100,000	1:1,000,000	1:10,000,000	1:100,000,000	Re-do dilutions?
count	375	105	11	1
answer

 

dilution factor	1:100	1:1000	1:10,000	1:100,000	Re-do dilutions?
count	TMTC	249	24	0
answer

 

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dilution factor	1:10	1:100	1:1000	1:10,000	Re-do dilutions?
count	954	96	10	0
answer

 

dilution factor	1:10,000	1:100,000	1:1,000,000	1:10,000,000	1:100,000,000	Re-do dilutions?
count	TMTC	567	58	12	1
answer