Brew belt
 

I'm new to home brewing and started my first Chardonnay yesterday. I bought a brew belt to keep the temp constant and all the instructions tell me is raise or lower the belt to adjust temp. Can anyone tell me do I raise it up the demijohn to gain temp in the vessel or lower? The reason I'm asking is because the air lock bubbles are bubbling like crazy and that's supposed to be bad. Help please

Air lock activity just means production of alcohol and CO2, that is great!! Though, how warm do you want to get, what is the temp range for the yeast you chose?

Also if positioned low, the heat will rise and circulate thru the container; as you position higher the less consistent the heat distribution is.

Heat rises, so I would think the higher the belt, the more heat it holds. The temperature you maintain is more important than airlock activity. Maintain temp that's ideal for your yeast.

The temp range is 20-25 degrees for the yeast it is just a general wine yeast. So do you recommend putting the belt at the bottom of the demijohn?

So dealing with 20-25C aka 68-77F. The placement and need of the brew belt will depend on room temp and actual temp of your must. If you need to raise temp you go to lower third and it actually circulates up since heat will create sliUsually without belt the temp of fermenting must rises by 8F, though I have seen it rise higher and ferment literally cooked and wine was ruined (not mine). What yeast are you using? What is your room temp, and what is temp at middle of low-middle-upper portion of fermenter. What are you fermenting, because some fruits do better with a lower temp ferment, carries more fruity aromatics and tones into finished products, but also has to do with chosen yeast.

Also, have you confirmed your brew belt is safe for glass? Some on market are for plastic fermenters only.

Once I get the fermentation going well with a white wine I try to lower the temperature to 15C or so. This preserves the aromatics that might be lost during a fast fermentation, although it may take weeks for the fermentation to complete.

Yes the belt is safe for glass I checked before I bought it. I have the brew in the kitchen which is usually quite cool around 16c.
The yeast says it is a General Wine Yeast which the brew shop said would do for all wine brewing.

Well I started it off yesterday and the bubbles are appx 1 every second. I have the brew in our kitchen which is about 18c temp.

I would place it lower 1/3 for six hours and check temp of must. I never keep belt on for more than eight hours, with at least eight hours off. Helps if you can wrap in a mylar blanket when out of belt. 8on, 8off, etc. If you move belt to upper 1/3 the lower part of fermenter will cool off, and kind of happy medium in center on desired temp reached.

Sounds like the ferment has started fine. I would lower the temp 3 or 4 degrees at this point.