PhatFil wrote:thick isnt a description you hear regularly about a brew.. the 2 tools used usually to help determine progress of a brew are a hydrometer and taste buds.
a 'thick' liquid may not provide a reliable hydrometer reading and if outside expected values you can safely assume its gone way bad.
With normal brewing I would agree. But for high alcohol you are putting 8 kg of sugar into a standard fermentor to make 22.5 litres of alcohol and the standard method is to add sugar bit at a time rather than all together. So if the yeast is not fermenting the mixture then it does become rather a viscous liquid. Another word for viscous I suppose could be thick! The start s.g. reading if all sugar is added together would be somewhere around 1.150 which I would call viscous and some may call it thick.