Mike Rankin wrote:
I will be laying ceramic tile bit by bit over the week. I have heard that
the grout should be done at once and mixed in one large batch. If it were
mixed and done in small sections then it will not match. Someone told me
that water amount and temperature differences of small batches will show up.
Does this sound true?

Partially. On larger reidential tile jobs grouting can take a day or
two - obviously you're not mixing that up in one batch. You'll have to
take a break at some point, so the decision is where to take that
break. If you are consistent in mixing the grout by premeasuring grout
and water before mixing, and don't use ridiculous amounts of water
cleaning off the grout, you should have very minor variations in color.
If you take a break and finish a batch of grout on one wall in a
corner, you'll never notice the difference.

Darker color grouts are more subject to color variations. If I'm using
a lighter grout I really don't worry too much about where I knock off
for the day.

The biggest difference usually comes from using too much water during
cleanup. When you strike off the excess grout with the rubber float
make sure you take off as much as you can. When you're using the
sponge to cleanup the tile on the first go round, make that sponge
almost dry. The damp sponge advice you get is really open to
interpretation and a lot of people use far too wet of a sponge as it
makes cleaning off the grout much easier. Unfortunately it's not good
for the grout.

It's about timing - don't let the grout sit too long before cleaning
and don't start cleanup too soon, and about mixing accurately.

R