Do you wash your new DIY bottles to remove any residue left from the manufacturer? If no, I recommend rinsing them well with clean warm water. If you use chemicals(soap, etc.) to wash bottles with maybe try using just plain water.
I would then test the different types and brands of vg, pg, nic.
Are your flavorings capped and stored at room temperature?
I hope you can figure this out. Welcome to the forum.
P.S. - You could consider having you Tonsils removed.
@echochild Welcome to ELR bud. Glad you joined. 
^^This may be more cost effective.^^ Hehe
Best of luck dude! I hooe you’re able to solve the issue.
Who gets them?
I don’t know. I didn’t ask for mine back and they didn’t offer 
. What would you do with them? Wait… maybe I don’t want to know 
Do you have friends who are DIYing? Ask them for a bottle or two of their DIY achievements / exchange with them. This is the simplest way to find out if something is wrong with your ingredients (like nic/PG/VG) or your mixing technique OR is it really something you are allergic to.
If you don’t know anyone and can’t get DIY mix anywhere, not even in a store, then you should play elimination game; means vaping pure VG/PG for a day or two to see if there’s something irritating, then add nic to this for another day or two, then go further with sweetener and different profiles (same recipes for couple of days).
Do you use sweetener? It’s highly unlikely, but still… you might have a bad one (just thinking it must be something common for all recipes you make that are not store bought liquids; if it’s not PG/VG/Nic).
I wash the DIY bottles, luer locks, and everything with soap and water, then thoroughly rinse them a bunch to make sure there is no residue. I even tried not, and without soap too.
I’ve tried Nic, PG, and VG from all kinds of places over the last 10 years. Flavors are capped at room temp.
I could, and have been considering getting my tonsils removed, but right now would likely not be a great time. I’m high risk for covid, and a hospital is not always the safest place especially with surgery like that.
Sadly, I know no one who DIY’s :-/ I don’t tend to use sweetener, but have tested it too. I don’t like the taste of sucralose all that much.
So, I’m going to test pH. It’s one of the only things I have never thought to rule out. I have malic acid on the way, and some pH test strips coming too. I’m planning on testing the store bought stuff and my steeped stuff and some SnV to round it out. It would make sense… I’m not a fan of cigar smoking. It’s super irritating IMO, and cigars are more alkaline than cigarettes are.
Ok, so have Malic and pH test strips. The test strips are hard to read, so I’m ordering an electronic meter. But, from small testing, it does appear that the store bought juice is more acidic than my DIY. My guessitmate is the Store is about 6.0, where mine is about 7.5.
Testing the malic acid. I noticed that there was barely any difference in color with 1 drop per 20 mL compared to without. So I used a 2nd + 3rd drop, and now it’s registering color wise in line with the store bought. Will vape and test over the next few days.
Should get meter on Sunday for more accurate readings.
Ok, initial thoughts:
6 Mg Nic 10/90 No Flavors 3 drops of Malic in 20 mL. “SnV”
This is almost as smooth as the store bought. I don’t feel much of any irritation at the moment. Have been almost chain vaping to see if I could produce any irritation for about the last 20 minutes. Will give it a break, come back to it tomorrow. See how it handles as an ADV and if irritation occurs.
I have noticed increased salivation. Will need to make sure to hydrate more.
Sweet breads?
Ok, so I’m a little confused. I’m not sure if this pH meter has difficulties with more viscus liquids or I’m not cleaning it right between changes of liquids.
Don’t know if anyone can recommend a similar cost better one?
From what I tested… and I’m not 100% sure of the accuracy:
Store Bought = 7.38
My doctored no flavor above = 7.45
Cake Master Premade Liquid 6 MG Nic 25/75 = 8.42
Rug-ly Simple cheesecake (from youtube) 6 Mg Nic 10/90 = 8.11
Rug-ly Simple Fruit (from youtube) 6 Mg Nic 10/90 = 8.27
I tried doctoring the Simple Fruit to bring down the pH to around where the store bought is, but even adding a bunch (I think around 15 or so drops) only lowered the pH to about 7.90. I stopped there, because I’m not sure if something is up with this meter or not.
Edit: Bought another one (different brand) to check the accuracy of the first one, but I have to wait 24 hours before I can use it.
Got a new meter, appears to be more accurate:
Store Bought = 6.3
My doctored no flavor above = 7.5
Cake Master Premade Liquid 6 MG Nic 25/75 = 7.2
Rug-ly Simple cheesecake (from youtube) 6 Mg Nic 10/90 = 7.4
Rug-ly Simple Fruit (from youtube) 6 Mg Nic 10/90 = 5.5 (Malic was added last night and accidentally added too much because the other meter wasn’t registering the acid). This one though, has been smooth and not bothering me.
Store bought is about 1 pH lower than my DIY’s. Doctored the Cake Master Premade Liquid 6 MG Nic 25/75 = 7.2. Made 20 mL, it took 20 drops of TPA Sour (Malic) to get the pH to drop to 6.3. Will vape and test tomorrow.
you have just had shitty diy juice, Iv had plenty of shitty retail juice
I’m curious to know how it’s going
Been having other health issues. Haven’t been able to do any extensive testing yet 
Ok, other health issues taken care of and back to testing this. So far:
Mixed 1 Bottle of Island Mango (SC) - Wonder Flavours - starting pH was around 7.3 (I tested at pH 7.3, and pretty quick throat irritation, within a few hours of staring to vape it). I muddled around with this one trying to find a good flavor % and get the pH to about 6.4 (I have tested the store bought that doesn’t bother me several times since last I started and it always comes in around 6.4 pH). Never was able to get the flavor to super pop, but somehow in the process I got the pH too low, about 5.9. Island Mango must be acidic on its own, because I didn’t add any more Malic. Throat feels okish, sometimes its bothering me a little, sometimes not. Seems to depend on how much fluids, and what kind, I’m taking in.
On this bottle I’m being a bit more rigorous. I mixed without Malic and tested pH. This is what I mixed (20 mL bottle):
7 mg Nicotine target of 1.4 mL ( wasn’t sure what strength to aim for as I wasn’t sure how much Malic I would be adding… typically I vape 6 mg).
PG - 3.8 mL, VG - 14.6 mL, Flavor Island Mango (SC) 0.2 mL. → pH 7.8.
Added 0.1 mL Malic (Sour by TFA) → pH 7.0
Added 0.05 mL Malic → pH 6.7
Added 0.05 mL Malic → pH 6.5
Total Malic added = .2 mL to bring it as close as I could to 6.4 pH.
Seems like each 0.05 mL of Sour = approx 0.2-3 pH
I haven’t vaped it yet. I’m waiting for my old supply to run out, then rewick and clean my tank.
Time edit:
Ok, so been vaping the new pH 6.5 batch for about 2 hours now. Throat feels mostly fine… a little numb weirdly though. I may not be drinking enough water, so I’m going to try that.
I can’t taste this flavor much. 1% seems too low, but my previous attempt got up to about 6-8% and it was still a pretty weak flavor. May try next batch with a premade mix I know the flavor amount.
Good luck mate, I am interested to see your results. I used to get irritation from commercial juice but have not had any (except for citrus based mixes) since starting DIY.
Is the higher PH more acidic or alkaline? I have issues with anything acidic in foods and with lemon or orange vape juices. Really annoying as I like the taste of things like Lemon Meringue but cannot eat or vape it…
pHs less than 7 are acidic while pHs greater than 7 are alkaline (basic)
So, most of my base DIY vapes come out basic (Which, if memory serves me correctly, is about right because Nicotine is a Base if I’m remembering right, and I think PG is also a Base.
Sorry to hear you aren’t tolerating flavors you like. Maybe you should also be testing pH. Maybe if you could get your vapes more Basic, you could tolerate those?
It’s really only with that particular flavour profile which I can live without. My custards are still good, which is all that matters! 
Citrus in foods causes me heartburn and regurge which is painful and annoying. In vapes it irritates the hell out of my throat so thinking that is the acids on both counts. Milder creamy flavours are fine and Nic has been fine too (18mg when I started, 1mg now MTL only).
I mix at 70% VG min, usually 80 to 85% depending on flavour content. PG doesn’t seem to irritate but I don’t really like much throat hit.
Sounds like we have somewhat similar boats. I also have reflux. I’m also not a huge fan of TH. I was very confused when I first started vaping and all people talked about was TH because I never really had that with stinkies. I understand it very well with too much PG now though.