Using drops alone to measure/mix, not very accurate.

Status
Not open for further replies.

jpasint

Super Member
ECF Veteran
Verified Member
Feb 2, 2014
464
898
Coconut Creek, Florida
I'd always assumed, that from a technical standpoint, mixing by drops instead of by volume or weight would not be the most accurate method.
What I didn't realize was just how much of a difference each vendor’s or reseller’s bottles would vary from each other. I assumed that the bottle and tip being used by each brand, vendor or reseller would make the biggest difference. Based on some of my tests, it seems there must be some (not so tiny) inconsistencies in the bottles/tips being used by the vendors and resellers.

I decided to test a handful of flavors that I have from the various manufacturers and resellers.
Some of my flavors are directly from the manufacturer and some are not. My point is not to prove one brand or reseller has bigger drops than the other but to just show how varied they all are.

My new scale (can't believe I waited sooo long) is accurate to .001 grams and has a repeatability rating of .001 as well. I tested each of the flavors below two separate times each and weighed four separate drops for each flavor. Although the drop weight varied sometimes within a specific four drop test cycle for a flavor, the amount of the difference was always somewhere between .001 and .003 grams, somewhat minor so I just averaged the total. The repeated second test for each flavor was always within the same range.
My drops were slow and methodical. The drop size could increase by almost 20%-30% if you squeeze the dropper harder to create a fast drop, so I tried to stay slow and consistent.

As stated in various threads here, if you alone are using your mixes and the results are repeatable, then you are good to go. That is not the point of my test.

Included below is the drop weight, drops p/ml, flavor brand, bottle size and flavor for each entry. I did two test flavors for some of the brands because I had them handy and I thought it would add to the idea that even using the same brand, vendor or reseller, mixing by drops is not all that accurate. For the sake of simplicity, the number of drops per ml is assuming 1 ml = 1 g.

.022 g = 45 drops p/ml
MFS
15 ml
Tropical Punch

.012 g = 83 drops p/ml
NF
10 ml
Menthol

.011 g = 91 drops p/ml
HS
10 ml
Caramel

.012 g = 83 drops p/ml
HS
10 ml
Coconut

.018 g = 56 drops p/ml
TFA (HV label)
30 ml
Bittersweet Chocolate

.026 g = 38 drops p/ml
FW
30 ml
Rocky Road

.020 g = 50 drops p/ml
FW
30 ml
Gummy Bear

.022 g = 45 drops p/ml
CAP
15 ml
Strawberries & Cream

.027 g = 37 drops p/ml
CAP
15 ml
French Toast

.031 g = 32 drops p/ml
FA (PV label)
3 ml
Custard

.026 g = 38 drops p/ml
FA (PV label)
3 ml
Maple Syrup

.028 g = 36 drops p/ml
SIG
30 ml
Cinnamon Sugar Cookie
 
Last edited:
  • Like
Reactions: capthook

jpasint

Super Member
ECF Veteran
Verified Member
Feb 2, 2014
464
898
Coconut Creek, Florida
Careful, I've posted this here a few times:

"Drops...twice the work for half the accuracy"

...and upset some "droppers"...like you said if it works for them, fine, but they'll never convince me it's more accurate, or less labor intensive, than a syringe.

Well, this drops to ml topic could help explain to some new DIYers why their mixes taste off.

If my testing contributes to help some folks, then it was worth the time to post my results.

I guess if some are insistent on using drops, I would suggest using the same size eye dropper to ensure that results are at least somewhat close, and over time, more repeatable.
 

Norrin

Super Member
Aug 29, 2014
677
780
Shetland
The first time I tried adding something by drop I could see that it was well wrong, I hit whatever the drops I was supposed to put in and it was slightly over half the volume I needed. I binned this idea quickly and have never tried to use it again. I knew it would be inaccurate but your work shows just how useless it is, unfortunately you will probably get more stick than praise.
 

dannyv45

ECF DIY E-Liquid Guru
ECF Veteran
Verified Member
Apr 12, 2013
7,739
8,424
New Jersey
www.e-cigarette-forum.com
Ive never used drops as I always thought it was blatantly obvious just how inaccurate it is as a measuring system (no offence meant to any droppers). Ive been using syringes but considering moving to a scale so that my results are easily and accurately duplcated.

I use drops when using inawera flavors because that seems to be the standard that everyone's using for that particular flavor manufacture. I also use drops when a small amount is needed like 1 drop or .025ml but other then that I use syringes.
 

derogg

Super Member
ECF Veteran
Feb 27, 2014
452
247
Socal
Temperature plays a big variable too. For example I have some Hangsens flavors with the metal needle tip droppers. Well I had originaly measures close to 100 drops per ml (Socal room temp mid 70s). I store my flavors in the fridge.I had calculated 70 drops (7% flavor) was to weigh 0.84 grams. Straight out of the refridgerator Highway was already over my calculated weight to 0.89 grams at 60 drops and Indian was at 0.85 grams at 47 drops.
Obviously this is purely academic, but goes to show there are a lot of variables at play in trying to make a truley accurate and repeatable mix.
Lucky for us DIY folk it still taste good!!
-Dirk
 

Norrin

Super Member
Aug 29, 2014
677
780
Shetland
Temperature changes volume too and since the ingredients have a different density the changes will be....ah who cares I never measure that accurately anyway. If you need/want to be accurate and be able to repeat exactly what you did weight is the way to go as this is fixed and it is easier to measure really small weights than volumes. Use what suits you though and be happy, still great that the info is being spread so that people can make informed decisions rather than thinking something is exact when it's not.
 

Mrdaputer

Ultra Member
ECF Veteran
Apr 28, 2014
1,209
663
MN
I use drops when using inawera flavors because that seems to be the standard that everyone's using for that particular flavor manufacture. I also use drops when a small amount is needed like 1 drop or .025ml but other then that I use syringes.


I agree 99% all tho there is one recipe I make that I use drops. It was when I first started out and didn't have a small syringe so I used drops. I was making 5 ml of a special apple pie. It was spot on so now I just triple the recipe. I don't dare try any other way lol. Sometimes I wonder if I should get what I need to do it by weight?
 
Status
Not open for further replies.

Users who are viewing this thread